A question for Canon shooters...

[Gary Irwin]

Hi All;

I'm an avid wildlife shooter heavily invested into Nikon and thinking of sinking even more funds into longer glass but am also finding myself "looking over the fence" at the Canon Camp. I've always envied Canon for the wider selection of glass and am intrigued by the new telephoto's coming down the pipeline, especially their low weight. But my question relates to bodies and sensor size.

I currently shoot FX and DX (D3/D300) but use my D300 90% of the time because I need the reach. I'm considering adding a 600VR and D3x/D4 to my stable for the better resolution and better ISO performance but the loss of reach going to full frame is a real sticking point for me as the birds around here are mostly of the smaller variety. Spending a fortune on long glass just to give it all back to full-frame sensor makes little sense to me.

On paper the Canon 1D4 seems to provide a good mix of features I'm looking for: 16 MP, 1.3 crop factor, hi FPS, pro AF.

I'm curious as to what the majority of Canonites prefer for avian photography. I would assume it's the 1D4 (1st) and 7D (2nd) but do see some shooting FX with the 5D as well.

Any and all comments appreciated.

[Doug Brown]

The 1D IV is the gold standard for birds IMO. It has the right balance of pixel density, high ISO noise performance, frame rate, and durability. Combined with either the new Canon 500 or 600, you'll have a formidable combination.

[arash_hazeghi]

I prefer D3S over 1D4 for avian photography if you have the 600VR (I have used both), it is a better camera in terms AF, IQ and features IMO. The new light Canon 600mm IS might be a game changer but it is considerably more expensive than the Nikon and who knows when it will be available. In general, I would say that if conditions are such that you cannot make a good image with your advanced Nikon gear, you won't be able to with Canon gear either.

[Gary Irwin]

The 1D IV is the gold standard for birds IMO. It has the right balance of pixel density, high ISO noise performance, frame rate, and durability. Combined with either the new Canon 500 or 600, you'll have a formidable combination.

Thanks Doug. Indeed, it's hard to disagree with that logic. Not that Nikon is any slouch, of course, but I'm beginning to question if Nikon has the best overall system for avian photography.

The 1D4 has been out for about 1.5 years...any scuttlebut as to when it might be replaced? I'm assuming not for at least another year.

[Gary Irwin]

I prefer D3S over 1D4 for avian photography if you have the 600VR (I have used both), it is a better camera in terms AF, IQ and features IMO. The new light Canon 600mm IS might be a game changer but it is considerably more expensive than the Nikon and who knows when it will be available. In general, I would say that if conditions are such that you cannot make a good image with your advanced Nikon gear, you won't be able to with Canon gear either.

Thanks Aarash, I appreciate your comments.

In fact I do believe the D3s is the better camera overall, but I see the 1D4 as having two key advantages (for me): higher MP and the crop factor. Other than superior ISO capabilities, the D3s really doesn't offer much more than my D3, which I find too short on my 500VR even with TC's. And the D3x provides the needed resolution boost but lacks the crop factor and ISO performance is isn't as good my D3.

To be honest, if it wasn't for the new Canon supertele's (I shoot mostly hand-held so the weight is a huge factor to me) I probably wouldn't consider switching. But it seems prudent to review all options before dropping another $20k into this hobby.

[John Chardine]

Gary- Sensor size has nothing to do with "reach". This is the so-called "crop-factor" myth referenced frequently by Roger Clark. What is important is pixel density. The D3x you mention has much more "reach" than the D3s even though the sensor size is the same.

I totally agree with Doug Brown's comments above.

I will add this- a recent robbery at home essentially means that I will have to start from scratch. I will stay with Canon. Further, I could get the 7D and wait for the 1DV but the 1DIV is just SO GOOD that I will go with that body again. I am afraid that Canon will up the pixel density with the mark V and I just don't need it. 16mp spread across a 1.3 crop factor sensor is as close to perfection as it gets for me. The noise on the 1DIV is industry-leading for the pixel size and density (ref. Roger Clark's web site). It's fair to say that noise will continue to get better and better with newer bodies but I don't need a low-noise 24 or 32+ mp camera, and my computer and hard drives don't need them either.

[Gary Irwin]

Gary- Sensor size has nothing to do with "reach". This is the so-called "crop-factor" myth referenced frequently by Roger Clark. What is important is pixel density. The D3x you mention has much more "reach" than the D3s even though the sensor size is the same.

I totally agree with Doug Brown's comments above.

I will add this- a recent robbery at home essentially means that I will have to start from scratch. I will stay with Canon. Further, I could get the 7D and wait for the 1DV but the 1DIV is just SO GOOD that I will go with that body again. I am afraid that Canon will up the pixel density with the mark V and I just don't need it. 16mp spread across a 1.3 crop factor sensor is as close to perfection as it gets for me. The noise on the 1DIV is industry-leading for the pixel size and density (ref. Roger Clark's web site). It's fair to say that noise will continue to get better and better with newer bodies but I don't need a low-noise 24 or 32+ mp camera, and my computer and hard drives don't need them either.

Hi John;

I do understand the differences between "reach" and "crop factor", but there's no denying the single most obvious effect of "crop factor" is the "apparent reach" that results. I'm also painfully aware that APS-C sensors come with limitations, which is why I'm prepared to go to longer glass and bodies with "pro" sensors and features.

Sorry to hear about your recent material loss, but I'm not really surprised to hear your staying with Canon. Thanks kindly for the note!

[John Chardine]

Hi John;

I do understand the differences between "reach" and "crop factor", but there's no denying the single most obvious effect of "crop factor" is the "apparent reach" that results. I'm also painfully aware that APS-C sensors come with limitations, which is why I'm prepared to go to longer glass and bodies with "pro" sensors and features.

Sorry to hear about your recent material loss, but I'm not really surprised to hear your staying with Canon. Thanks kindly for the note!

Hi Gary- It really is deniable, and it really is a myth! If you look at two images at the same magnification on your monitor from two cameras with the same pixel density, one with 1.0 crop factor and the other with a 1.6 crop factor, the inner parts of the image will look identical. With the 1.6 crop factor image you will be missing a band around the edge of the image, that's all. The key part of this is that you are viewing the two images at the same magnification. You have to standardise magnification or you are comparing apples and oranges. I know you understand this but you just have to think about it more.

[Jim Neiger]

Ditto what Doug said.

I've got the new 600mm on order. Coupled with the 1d Mark IV it should be the ultimate tool.

[Gary Irwin]

If you look at two images at the same magnification on your monitor from two cameras with the same pixel density, one with 1.0 crop factor and the other with a 1.6 crop factor, the inner parts of the image will look identical.

No worries John, we're on the same page. Your statement is theoretically correct...but from a practical standpoint full frame and crop cameras don't have same pixel density, which is key to the issue.

[Gary Irwin]

Ditto what Doug said.

I've got the new 600mm on order. Coupled with the 1d Mark IV it should be the ultimate tool.

Thanks Jim, that 1D4 and 600 IS II combo is the one I'm seriously considering. Matched with the new 200-400 and 70-200 (love my Nikon versions) would make a killer wildlife kit.

Lots to think about.

[Eric Weaver]

I wish I had the new 600 mm and a 1D4. I'm wondering how IQ will stack up on the 600mm and 1.4 TC against the 800mm.


John,

I think the biggest advantage to the crop sensor cameras is that the bird takes up more of the frame. You say so what just magnify it. I don't know how the weather is where you live but where I am I seldom have perfect days for shooting. In the winter it is typically gray skies for months on end it seems. I have a 5DII and a 7D. I'm the first to say that the 5DII is a much better camera than the 7D but if the birds are far away and the conditions are not so good I'm usually better off shooting with that 7D so that I don't have to do severe crops just to get the bird big enough to see it. This could be different with Canon lenses. All I own are old Leicas made for film. Color aberration can be a problem in poor lighting. The "larger" bird in my viewfinder makes manual focusing much easier too.

Yes, I completely understand the crop factor sensor. If you want to take it the other way a 90mm on a 4x5 is a wide angle because that light has to cover a much larger sensor or film. The field of view changes and that is the important part of the equation. Obsession with actual focal length is rather pointless in my opinion. A 600mm lens gives a wider angle of view on a "full frame" sensor than on a crop sensor merely because the sensor is taking up less of the light taken in. You stick your bird in the center of that viewfinder and your 600mm lens gives the same field of view as a 960mm on a full frame. It doesn't make the focal length any longer but it does give you a larger object on your sensor at the same distances as full frame. There are advantages at time to not having to blow up your image. I think most photographers who've been at it awhile understand this. I really think guys who give your argument are the ones who need to think about it more. It's a pointless debate. One that's nice to explain to newbies to dazzle them with then forget about it. There are advantages and disadvantages to crop sensors. Tighter field of view is an advantage for small objects at long distances. Quality of the sensor tends to be a disadvantage. There are others on both sides of the equation.

[Eric Weaver]

One last thing. The tighter the crop the better your image has to be. Try making a billboard size print out of one of your images sometime. Small objects, poor lighting, hand or monopod held, general field conditions are not conducive to getting perfect images. We aren't sitting in a studio taking pictures of these little birds. Narrower field of view is a distinct advantage in the real world of bird photography. I suppose if I could mount my lens on the 5DII and have it tethered to a laptop for micro focusing and have perfect lighting and all the birds I wanted to see would kindly come pose for me while I did my thing... Oh yeah, I don't have auto-focus anyhow. That won't work either.

[John Chardine]

Hi Eric- The reason you would pick up the 7D rather than the 5DII in a focal-length limited situation like you describe is that the 7D has a significantly higher pixel density than the 5DII, not because the 7D has a "crop-factor" sensor.

On the topic of light, I live on the east coast of Canada, so we get frequent cloudy days. This is a huge advantage for wildlife photography. If I can avoid it I don't go out on sunny days, or limit shooting to early or late.

[John Chardine]

No worries John, we're on the same page. Your statement is theoretically correct...but from a practical standpoint full frame and crop cameras don't have same pixel density, which is key to the issue.

Hey Gary, ...... and cameras with the same crop factor don't have the same pixel density either. Right now I can think of FF bodies like the Nikon D3s or Canon 5DI at 12mp, the Canon 1DsIII and 5DII at 21mp and the Nikon D3x (and one of the Sony's) at 24mp. All I am saying is that the important variable or factor in comparing "reach" is pixel density, not sensor crop factor. Once you have defined pixel density, sensor size is then important in determining how big the pixels can be, which is as you know important when considering the amount of noise produced.

Sorry to flog a dead horse but this is an important topic to get right.

[Eric Weaver]

I truly wish the 7D had a lower pixel density. It is too noisy the way it is. The 1DIV has a much better density. As for clouds. Partly cloudy is best. I don't know what you have up there but down here it turns light gray in the winter and stays that way. It is in a word horrible lighting. My pics on blue sky day are always better than the gray sky days. The 5DII handles that better than the 7D by far but not being able to see that tiny little bird to manually focus more than outweighs the disadvantages of the 7D. I don't think you're taking in the entire gist of my posts. I'm not likely to change your mind and you're not likely to change mine on it. Might as well leave it at that and we both know the other guy is clueless.

See your last post after posting. It is an important topic to get right. I wish you'd get it straight! ;)

[David Stephens]

Comparing the 7D and the 1D MkIV, the 7D doesn't have as sophisticated and fast AF system, it unable to AF quickly with TCs that take it beyond f/5.6. However, its pixel-density is close to ideal for showing feather detail, etc. I own the 7D and only envy the 1DMkIV's AF with TCs. I prefer it's more compact body and find the weather sealing adequate for my use in the wet and below-zero conditions that I find in Colorado.

Starting from scratch, with new Series II lenses anticipated with new Series III TCs, I'd suggest the 1D MkIV.

[Eric Weaver]

I'll take the 1D mkIV over the 7D any day of the week. Not all pixels are created equal. The 7D does do well under good lighting and a good tripod. I have some excellent pics from it in that manner. The 1D4 and auto-focus lenses are both out of my budget though.

[Craig Markham]

I've been watching for months for a Mk4, at the MSRP of $4999. B&H has it listed at that price, but it's been "temporarily out of stock" for months. Hunt's is "backordered". Even Canon USA's own retail site lists it as out of stock. Amazon occasionally puts one up at $6495 -- jeeze! Anyone have a good clue as to what's going on? Canon seems to be merrily hawking its new pocket cameras all over the place, but doesn't seem to be able to scratch up a Mk4 for anywhere near the MSRP.. Is this just another round of Canon's "withhold-and-gouge" market strategy, or was the Mk3 fab located at the Fukushima dai-chi nuclear plant?

[Eric Weaver]

Adorama has it for $5499. That's as cheap as I've seen it in awhile. I would imagine the earthquake is at least partly responsible for the shortage. Price gouging and the weak dollar likely contribute as well.

[John Chardine]

I've been watching for months for a Mk4, at the MSRP of $4999. B&H has it listed at that price, but it's been "temporarily out of stock" for months. Hunt's is "backordered". Even Canon USA's own retail site lists it as out of stock. Amazon occasionally puts one up at $6495 -- jeeze! Anyone have a good clue as to what's going on? Canon seems to be merrily hawking its new pocket cameras all over the place, but doesn't seem to be able to scratch up a Mk4 for anywhere near the MSRP.. Is this just another round of Canon's "withhold-and-gouge" market strategy, or was the Mk3 fab located at the Fukushima dai-chi nuclear plant?

Hi Craig- I bought my replacement 1DIV recently from Aden Camera in Toronto. It was in stock and cheaper than B&H. It seems they are in Canada. Camera Canada has them too, or can get them from Canon Canada in a day or two. The two $$ are virtually at par now so the transaction is pretty transparent. I have no affiliation with Aden.

http://www.adencamera.com/product-ov...043&Category=6

[Craig Markham]

Thank you, so much, John! I just placed my Mk4 order with Aden (they owe you ). With a field photography workshop coming up in the California eastern Sierras in October, I wanted to get some lead time to be sure I know the camera well before then. Shouldn't be much of a operational change from my current Mk3, except for the addition of video. I'm looking forward to getting more pixels on the subject.

I'm with you on the discussion above re pixel density vs crop factor. The crop factor "advantage" is only slightly less bogus than a "digital zoom" sales pitch for consumer cameras. But come to think, they are virtually the same -- digital zoom applies a digital crop factor (uses fewer pixels so that the image will appear larger in the viewfinder), the adverse effects of which quickly show up on images from small pocket camera sensors. A 1.3 sensor applies an optical crop factor. The really bad thing about "digital zoom" is that the sucker that uses it is stuck with a small, cropped, noisy image.

If the subject is too small to see well in the viewfinder, and the photographer wants an optimal image, he'd better move in closer or get longer glass. My rule of thumb is, if the key subject doesn't span the central circle in my viewfinder, the cropped image will be marginal, except perhaps as a "record" or ID shot.

Again, thank you for the referral. I'm now $5000 poorer, but pixels richer!

With best wishes,
Craig

[Eric Weaver]

Digital crop and physical crop are not the same thing. It's not even close.

I guess you've never had a shot across the river in the middle of January. Sometimes 800 mm just isn't close enough. I don't have auto-focus. Sorry I just don't have the money for it. Bigger in the viewfinder is a major benefit. Digital viewfinders are also not made to work with manual focus lenses. Many variables for me that you likely aren't dealing with. Yes, those are often just for record. I'm compiling a personal data base of every bird species I've seen. Hopefully they will be replaced with better pics along the way. Until then I live with whatever I can get and sometimes that is less than ideal.

Congrats on your purchase. I don't own the 1D4 but had the opportunity to briefly use one once. It was nice.

[Craig Markham]

Digital crop and physical crop are not the same thing. It's not even close.

I guess you've never had a shot across the river in the middle of January. Sometimes 800 mm just isn't close enough. I don't have auto-focus. Sorry I just don't have the money for it. Bigger in the viewfinder is a major benefit. Digital viewfinders are also not made to work with manual focus lenses. Many variables for me that you likely aren't dealing with. Yes, those are often just for record. I'm compiling a personal data base of every bird species I've seen. Hopefully they will be replaced with better pics along the way. Until then I live with whatever I can get and sometimes that is less than ideal.

Congrats on your purchase. I don't own the 1D4 but had the opportunity to briefly use one once. It was nice.

Hi Eric,
Well, without arguing this further, but to clarify I hope, I said that optical crop factor and digital zoom [of a given sensor/lens combination] are virtually [i.e., not literally] the same in their effects on the number of pixels represented in a recorded image. I certainly do not equate them, and I do of course use cameras that have sensors smaller than full frame. I NEVER use digital zoom on any camera.

RE the manual focusing issue, have you tried using Live View to to help you focus those long-range record shots? The LV 5x & 10x magnification on the camera monitor helps a lot for fine-focusing. Just be sure, especially in your cold-weather shooting environment that you have warm, fully charged batteries on hand, since LV does increase the battery drain.

Yes, I have spent my share of hours out in stinking cold weather. My sympathies.

[Eric Weaver]

Sorry Craig, they aren't even virtually the same. I think you either don't understand a crop sensor or you're over simplifiying it. The other choice would be that I don't understand what you're trying to say. It's really not worth arguing about though. I've seen this argument too many times on too many forums. Nothing good ever comes of it. I should have just let it go. You can't fight city hall.

I do use live view when I can. I'm not always on a tripod though. Kind of hard to do it handheld or with a mono. Even on a tripod at long distances it can be troublesome. You touch the lens to focus and the picture shakes. The wind blows, the picture shakes. You let it settle down the bird flies away. Best results usually come by sitting in a blind waiting for them to show up. I'm much better at that in the summer than I am in the winter. I'd never make a good ice fisherman. I can't sit around waiting for summer to show up either. Have to get out. Do the best with what I have and hope for a few good ones along the way.

[Roger Clark]

I think the biggest advantage to the crop sensor cameras is that the bird takes up more of the frame. You say so what just magnify it. I don't know how the weather is where you live but where I am I seldom have perfect days for shooting. In the winter it is typically gray skies for months on end it seems. I have a 5DII and a 7D. I'm the first to say that the 5DII is a much better camera than the 7D but if the birds are far away and the conditions are not so good I'm usually better off shooting with that 7D so that I don't have to do severe crops just to get the bird big enough to see it. This could be different with Canon lenses. All I own are old Leicas made for film. Color aberration can be a problem in poor lighting. The "larger" bird in my viewfinder makes manual focusing much easier too.

Eric,
I agree with John on this issue. The 5DII versus 7D are cameras with two different purposes, like pliers and a screw driver. The sensor in the 7D actually has slightly better system sensitivity, so by that measure it has lower noise. In fact if you use a given lens, like 500 f/4 and image a bird wide open with the 7D, then put on a 1.4x TC and put the 500+1.4x on the 5DII, the detail on the subject would be virtually identical, the pixels on the subject very close, and the noise slightly better on the 7D for the same exposure time! I'll give the detailed reasons below.

Yes, I completely understand the crop factor sensor. If you want to take it the other way a 90mm on a 4x5 is a wide angle because that light has to cover a much larger sensor or film. The field of view changes and that is the important part of the equation. Obsession with actual focal length is rather pointless in my opinion. A 600mm lens gives a wider angle of view on a "full frame" sensor than on a crop sensor merely because the sensor is taking up less of the light taken in. You stick your bird in the center of that viewfinder and your 600mm lens gives the same field of view as a 960mm on a full frame. It doesn't make the focal length any longer but it does give you a larger object on your sensor at the same distances as full frame.

While I understand your argument about the apparent size of the subject in the viewfinder, note that the full frame cameras have a larger viewfinder, so it is not that simple. The 7D viewfinder magnification is 1.0x and the 5DII is 0.71x. If it was crop factor only, is would be 0.62x. But in either case, critical focus can't be achieved with the viewfinder design of modern DSLRs, so simply use live view and magnify the image as desired. Seems like a non issue to me.

There are advantages at time to not having to blow up your image. I think most photographers who've been at it awhile understand this. I really think guys who give your argument are the ones who need to think about it more. It's a pointless debate. One that's nice to explain to newbies to dazzle them with then forget about it. There are advantages and disadvantages to crop sensors. Tighter field of view is an advantage for small objects at long distances. Quality of the sensor tends to be a disadvantage. There are others on both sides of the equation.

There are some misconceptions here. The sensor quality is NOT a disadvantage with "crop" sensors. There are four fundamental factors in imaging with digital sensors: 1) The diameter of the lens, 2) focal length of the lens, 3) the size of each pixel, and 4) exposure time. The 5th parameter is the system sensitivity of each pixel, but the system sensitivity is quite constant among digital cameras within a couple of generations among all the manufacturers (for the data I have seen). Let's make exposure time constant so take it out of the mix and note that ISO does not change sensitivity; it only changes exposure time and post sensor amplification. Now we have lens focal length and pixel size as controllers of detail on a subject (assuming lens aberrations do not limit detail). Given two cameras, let's say with pixel sizes like the 7D (pixels = 4.3 microns) and 5DII (pixels = 6.4 microns), and we only change focal length to match detail, then the noise will be the same. The reason is the amount of light has not changed: the lens opening is the same so gathers the same amount of light per second. If we've changed focal length to match resolution, then the light per pixel is constant. So if the the 5DII is used on a lens with 6.4/4.3 = 1.5x longer focal length (1.4x TC would be close enough), the number of pixel on the subject, the detail on the subject and noise per pixel would be so close you would need instruments to measure the difference.

The bottom line is physical aperture diameter gathers the light, focal length spreads out the light, and pixels chop up the light. When pixel size / focal length is the same for a given lens, then the resolution on the subject and the signal-to-noise ratio per pixel are identical. This means that a 500 mm f/4 lens on a 7D with deliver essentially identical images in terms of detail and signal-to-noise ratio as a 5DII + 500 mm +1.4x TC given the same exposure time (and of course over the common image field of view).

Crop factor is not part of the equation except for field of view. I would much rather have a full frames sensor with the same size pixels as a cropped sensor. For example, choose between a 30D and 5DII. They have the same pixel size, so if you crop the 5DII images by the 1.6x crop factor, you would have images the same size, field of view and pixels on subject as the 30D. I look forward to a full frame sensor with pixels the size of the 7D (that would be 46.7 megapixels!). The advantage of the larger field of view is in following rapidly moving subjects and not cutting off body parts, like wings.

If one wants more light per pixel (higher signal-to-noise ratio), there are only two choices (note again that pixel efficiency in modern DSLRs are essentially the same): bigger pixels and you lose detail and pixel on the subject, or a larger diameter lens to deliver more light per exposure time per pixel. Again, crop factor is not part of the equation. For example, move from a 300 mm f/4 to a 300 mm f/2.8 lens gives more light while maintaining detail. Moving from a 7D to a 5DII loses resolution with the same lens, thus the given lens puts more light into the larger pixel.

I see people complain often about the noise in 7D images. But if detail on the subject is equalized among all current generation cameras using constant lens aperture and changing focal length (e.g. with TCs), whether Nikon, Canon, Sony, etc, they would all produce nearly the same noise levels, and in fact, the 7D would edge out most if not all others. This is a good thing, as consumers can choose what they want: more detail + more noise, versus less detail and less noise. But to make that decision, one needs to understand the trade, and it seems few do. For those who want both fine detail and low noise (e.g. bird photographers), there is no free lunch, literally--you must buy the biggest lenses to deliver the light. The largest lens supertelephoto is the 600 f/4 with 150 mm diameter clear aperture. (Well, the largest under $20,000.)

Roger

[Eric Weaver]

well it just goes to show you can't fight city hall...

it's late, I'll have to get back to it when I'm not half asleep and have more time. I see some holes even at this late hour. Better left till later.

[Craig Markham]

Eric,
I agree with John on this issue. The 5DII versus 7D are cameras with two different purposes, like pliers and a screw driver....

Roger

Though this discussion has drifted rather far from the original Canon/Nikon question, I appreciate your coming in with your, characteristically nuanced explanation of this complex subject of noise/resolution/light-gathering capacity/image size. Thank you kindly.

-Craig

[Craig Markham]

.... It's really not worth arguing about though. I've seen this argument too many times on too many forums. Nothing good ever comes of it. I should have just let it go. You can't fight city hall.

Agree, but I've never thought of myself as "city hall".

I do use live view when I can. I'm not always on a tripod though. Kind of hard to do it handheld or with a mono. Even on a tripod at long distances it can be troublesome. You touch the lens to focus and the picture shakes. The wind blows, the picture shakes. You let it settle down the bird flies away. Best results usually come by sitting in a blind waiting for them to show up. I'm much better at that in the summer than I am in the winter. I'd never make a good ice fisherman. I can't sit around waiting for summer to show up either. Have to get out. Do the best with what I have and hope for a few good ones along the way.

If the camera can't be steadied enough to keep the subject image from jumping around the screen in live view at 1x while you focus, it will probably be jumping around too much to make a sharp image, especially with only a precious few pixels on the item of interest. I understand, however, that LV does require some extra futzing, but you may be able to take care of that by using LV to pre-focus your setup for the long distance you describe, and then turning it off and using the viewfinder to recompose and shoot. Good luck with it. I trust you haven't been freezing your fingers the last couple of months.

-- Craig

[John Chardine]

snip

A 600mm lens gives a wider angle of view on a "full frame" sensor than on a crop sensor merely because the sensor is taking up less of the light taken in. You stick your bird in the center of that viewfinder and your 600mm lens gives the same field of view as a 960mm on a full frame. It doesn't make the focal length any longer but it does give you a larger object on your sensor at the same distances as full frame. There are advantages at time to not having to blow up your image. I think most photographers who've been at it awhile understand this. I really think guys who give your argument are the ones who need to think about it more. It's a pointless debate. One that's nice to explain to newbies to dazzle them with then forget about it. There are advantages and disadvantages to crop sensors. Tighter field of view is an advantage for small objects at long distances. Quality of the sensor tends to be a disadvantage. There are others on both sides of the equation.

The writing is a little unclear Eric so forgive me if I am not getting your meaning.

The size of an "object" projected by the lens onto your sensor has nothing to do with sensor size/crop factor as you suggest above. After all, the sensor is simply a projection screen placed behind the lens. The size of the Big Ben clock face on the sensors of a FF and 1.6 crop factor body, both with 600mm lenses mounted, and placed the same distance from the subject, will be identical. The scene will look different in each viewfinder but what matters ultimately to you as a photographer is what you record on the sensor. Your viewfinder view might be important to you for focusing or whatever, but that's another subject.

If you are still having trouble with this, consider macro photography. You may be familiar with the the 1:1 or 1:2 designation of macro lenses, AKA "reproduction ratio". Reproduction ratio is the ratio of the size of the object projected on the sensor over the real-life size of the object. Reproduction ratio depends on lens focal length and distance to subject, NOT sensor size. This is exactly what I'm talking about above.

[Desmond Chan]

The size of the Big Ben clock face on the sensors of a FF and 1.6 crop factor body, both with 600mm lenses mounted, and placed the same distance from the subject, will be identical. The scene will look different in each viewfinder but what matters ultimately to you as a photographer is what you record on the sensor.

I could be wrong but, I tend to think discussion like this is more academic rather than anything else. As far as the guy who is behind the camera is concerned, to most of them in the real world using the camera to take pictures, what matter is the fact that, with the use of a crop-factor camera, he or she can be farther away and still get a fill-frame shot. As far as image quality is concerned, your eyes should tell you about it (assuming you know what a good quality image looks like). Pixel size, pixel density...do you really need to know about them to select a camera, a lens, and be able to produce a good photograph?? Besides, there're so many variables in play when you take a picture. It seems me some over-thinking is happening somewhere.

But, it's like just me

[John Chardine]

It isn't academic Desmond, but even if it were, is that any excuse to ignore errors, myths, and misleading statements? If you want to ignore this then "fill your boots" as they say down here in eastern Canada. It's a free country. As a scientist, that's not how I do things.

The "crop-factor myth" is not "academic" as you suggest, and is widespread and pervasive; your comment shows you too have come under its spell. Here's what you said:

"with the use of a crop-factor camera, he or she can be farther away and still get a fill-frame shot."

Crop-factor cameras crop the image, as the term implies. The edges of the image are cropped off compared to what would be rendered on a FF sensor. This may make an object appear larger in the frame, however, this is irrelevant. What matters is how the sensor renders the object and that depends on pixel density, not on sensor size/crop factor. Regardless of how big an object is in the frame, if you have low pixel density it will be rendered with less detail, and if you have higher pixel density it will be rendered with more detail (I'm ignoring noise here for the moment). As Roger mentions above, the Canon 30D (1.6 crop factor) and the 5DII (FF) have the same pixel size (and roughly the same density- the fill factors were a little different on the sensors). At the same distance with the same focal length, an object will appear bigger in the frame of the 30D that it will in the frame of the 5DII because the edges are lopped off the cropped sensor. However, if you bring the two images into the computer at the same magnification (say 50 or 100%), the objects will look identical (again ignoring noise etc) because the pixel density is the same. The crop factor is irrelevant.

So why is this not an academic issue? The reason is simple. A full understanding arms you with the necessary information to make informed decisions about which camera body is best for your needs and which lenses best suit your applications. Say someone was considering the purchase of two bodies, one full frame, the other 1.6 crop factor, but they both had the same pixel density. Take the Nikon D3x (FF) and the Canon 7D (1.6 CF), which have roughly the same pixel density (ref. http://www.clarkvision.com/articles/...mance.summary/). For a bird photographer in focal-length limited situations, it might be a big mistake to think that you could buy a 400mm lens and mount it on the 7D and get better reach than if you bought a 500mm lens mounted to a 3Dx. If you believed the crop-factor myth, this is exactly what you would do and you would save money but be very disappointed. There are lots of other examples but this one should suffice.

Finally (and I apologize for the length of the message), I have spent a lot of time on this topic because I believe it is important for people to understand it. If I thought for one moment it was irrelevant as you suggest Desmond, I would spend my time doing other things like making images. I don't "over-think" just for the fun of it.

[Desmond Chan]

It isn't academic Desmond, but even if it were, is that any excuse to ignore errors, myths, and misleading statements? [snip]
As a scientist, that's not how I do things.

As I expected actually. Just like car guys like to talk about cars. Camera guys like to talk about camera. To the rest of the world, it's nothing worth spending too much time on.

The "crop-factor myth" is not "academic" as you suggest, and is widespread and pervasive; your comment shows you too have come under its spell. Here's what you said:

"with the use of a crop-factor camera, he or she can be farther away and still get a fill-frame shot."

For a bird photographer in focal-length limited situations, it might be a big mistake to think that you could buy a 400mm lens and mount it on the 7D and get better reach than if you bought a 500mm lens mounted to a 3Dx. If you believed the crop-factor myth, this is exactly what you would do and you would save money but be very disappointed.

I don't know about 7D, I only know it's a 1.6 crop factor camera. But, I do have both a full-frame Nikon and a crop factor Nikon. Are you saying that, if I want to get a fill-frame shot, I can stand at the same distance from the same subject and will get the same result with either of the cameras, even though when I look through the view-finders, I can see more in one than the other, and when I look at the file on my computer, one of the images clearly cover a wider angle of view?? I am no scientist, and I likely am also stupid. But, how can you tell me I am looking at the same thing?

I'm sure data help us understand things and thus allow further development to happen. From the points of view of many photographers out there, I'd say all that matters is what they see, and they make decisions based on that. Whether it is technically correct to define "reach" one way of another I'd leave it to you academic folks I do think, when I talk to many folks out there, when we use the term reach, we more or less know what we are referring to. I think that's what matters from the practical point of view.

But, discuss on, I would not expect otherwise. And I'm still reading.

[Gary Irwin]

Wow, these topics can get down into the weeds really quickly!

To me, the goal here is to put as many "quality" pixels on the subject as possible. Basically there are three ways of doing this; (1) get closer (2) increase magnification or (3) use a higher density (i.e. crop) sensor. Each method has benefits and trade-offs.

Getting closer is the most cost effective but often requires serious commitment in terms of time, patience use of blinds etc., and can't always be used. But if you can do it, getting close beats the other two methods hands-down.

Using longer lenses to increase magnification is a straight forward option except that adding TC's, atmospheric conditions over long distances and poor technique start to muddy the waters.

Use of high-density (i.e. cropped) sensors looks like an ideal solution at first, except that a lot of other factors start coming into play like the effects of anti-aliasing filters, more difficult noise suppression at higher ISO's and the need for high quality optics and good long-lens technique.

In the real world I draw on all of these things depending on the circumstances. No one solution is best for all situations.

[John Chardine]

I know what you mean in your first comment Gary. Too bad this happens. Best to ignore.

You have hit the nail right on the head with your goal and I think this is really good way of explaining the issue to people.

[Roger Clark]

Using longer lenses to increase magnification is a straight forward option except that adding TC's, atmospheric conditions over long distances and poor technique start to muddy the waters.

Use of high-density (i.e. cropped) sensors looks like an ideal solution at first, except that a lot of other factors start coming into play like the effects of anti-aliasing filters, more difficult noise suppression at higher ISO's and the need for high quality optics and good long-lens technique.

Gary,
The above two solutions are effectively equivalent. You can increase focal length (e.g. with a TC) to magnify the light over the large pixels, or you can reduce the pixel size to sample finer. If you increased focal length by 2x with a TC, versus a camera with half the pixel spacing and no TC, you get the same pixels on subject, same spatial detail, the same amount of light per pixel, same noise per pixel when using the same exposure time, and the same problems with atmospheric conditions, cameras movement, etc.

The way you win with more magnification is by also going to a bigger lens, e.g. 600 f/4 versus 300 f/4. It is the increase in lens aperture diameter that changes the equation. (And changes the budget!)

Roger

[Gary Irwin]

Gary,
The above two solutions are effectively equivalent. You can increase focal length (e.g. with a TC) to magnify the light over the large pixels, or you can reduce the pixel size to sample finer. If you increased focal length by 2x with a TC, versus a camera with half the pixel spacing and no TC, you get the same pixels on subject, same spatial detail, the same amount of light per pixel, same noise per pixel when using the same exposure time, and the same problems with atmospheric conditions, cameras movement, etc.

The way you win with more magnification is by also going to a bigger lens, e.g. 600 f/4 versus 300 f/4. It is the increase in lens aperture diameter that changes the equation. (And changes the budget!)

Roger

Hi Roger;

It appears were in agreement, and would only say that the increasing magnification and sensor density isn't quite the same because of the latters increased noise at higher ISO's. I will always choose (quality) higher magnification over pixel density because the big fat pixels on lower-density sensors are so much more tolerant of noise, poor technique and the use of TC's (to a degree).

Unfortunately in the game of avian photography I'm almost always pushing the envelope and have to rely on my cropped sensor D300 attached to my 500VR w/TC pretty well all the time.

However, Thom Hogan recently wrote an excellent summary on Nikon's "Exotic Lenses" and recommends pro bodies to get the most out of these expensive lenses. http://bythom.com/nikkor-telephoto.htm

Although not a dedicated avian shooter, Thom insists on quality imagery and told me his choice is the 400VR + D3x. Basically he goes for quality imagery first even if he can't crop as much as he'd like to. Indeed, I have noticed that pros and long-time avian shooters will more often sacrifice reach for quality of imagery. Maybe its because they've already got that "average" shot many times over and the only way they can raise the bar is to improve the quality -- and that means using top of the line equipment and getting close.

Anyway, I'm inclined to agree with him and am trying to decide whether I should spring for the D3x or look harder at the Canon 1D4. Normally I wouldn't think of changing brands as I love Nikon glass and bodies, but the idea of hauling around Nikon's 11lb 600VR has my back doing spasms!