Requesting Advice - Low Light Bird Photography

[Phil Richardson]

I recently completed a trip to Taiwan and was able to spend part of the time going after birds. I have a 7D and a 400 5.6L. The weather was overcast almost all the time, so overcast that there were no shadows and we even had light rain at times. As you can imagine, I was very unhappy with the resultant photos. Many of my shots were taken at ISO 2500 and 3200. Other settings were f5.6 and either 1/640 or 1/800. For 90% of the time I was shooting stationary birds. I must admit that I was aware this would likely be a problem before I left, but had no immediate solution. <o:p></o:p>

Although my rig performs adequately, if not ideally here in Southern California, I think the ultimate solution to being able to handle these types of conditions is to get a camera like the 1D Mark iv and a lens like the 500 4.0L (version 1). I am also considering the 300 2.8L for ease of travel, but I would prefer this thread not get into the relative merits of the two lenses. I have always shot handheld up to now, but I would consider getting a monopod for these types of conditions I encountered inTaiwan as a partial solution. Its not like I have the luxury to wait until two weeks later when the weather improvesto go back and reshoot. <o:p></o:p>

Getting both the camera and the lens is a big step for me. Cost is a big issue. So 500 4.0L II is not a consideration, nor is the 1Dx. I am aware of the controversy over whether the 1D4 or the 5DIII is a better bird camera. I don’t mean to start that discussion here. Lets say I have decided on the1D4. My question is first, will my proposal for both the upgraded camera and lens each make a significant difference in image quality? And second, which would have more impact on getting better shots, the camera or the lens, so I know which one to get first. Thanks in advance for your help and time.

[John Chardine]

Well honestly Phil I can't imagine. It's interesting, whenever people describe terrible light, meaning overcast, low light, I am filled with envy! OK bright overcast is great but full sun is not unless you have the ability to get out early morning or late evening. If the light is very bright (sunny) I generally stay in.

But to answer your question, you want to be able to handle low-light situations so you need a fast lens with good image stabilization and a camera that performs well at say 800 or 1600 ISO. As far as the camera is concerned, right now I would go with modern technology and consider a 5DIII rather than the 1DIV, but a used 1DIV would perform very well for you too. As far as the lens goes, the 300mm f2.8 II is terrific and if you invest in the 1.4 and the 2x teleconverter, you have a 420mm f4 and a 600mm f5.6 lens. This lens (as all the new Canon series II teles) performs extremely well with the TCs even wide-open. Again here I am advocating a series II lens rather than older technology.

[Loi Nguyen]

Phil, if you need the focal length, 500f4 is better than 300f2.8 + 1.4Tc = 420f4. I have been to Taiwan a number of times and can understand the gray sky, unattractive lighting, rainy weather. I have not used the 1D4, so can't help you there.

[Phil Richardson]

Thank you for the responses John and Loi. Yes Loi, some of my shots even have visible rain drops. A real test of the 400 5.6/7D combo. The luminance noise is unacceptable on most of my shots. My thought is that the better lens would make the biggest improvement. I was thinking that the IS would get me a few stops of improvement, plus the 5.6/4.0 advantage, allowing a significant reduction in ISO. I don't think the 1D4 would offer the same magnitude of advantage over the 7D.

[Loi Nguyen]

Thank you for the responses John and Loi. Yes Loi, some of my shots even have visible rain drops. A real test of the 400 5.6/7D combo. The luminance noise is unacceptable on most of my shots. My thought is that the better lens would make the biggest improvement. I was thinking that the IS would get me a few stops of improvement, plus the 5.6/4.0 advantage, allowing a significant reduction in ISO. I don't think the 1D4 would offer the same magnitude of advantage over the 7D.


Phil, the 500f4 I has older IS rated at 2 stops vs. the new 300f2.8 II IS at 4 stops. So if shooting at lw SS is the main motivation, I think John's advice is a good one here. You lose a bit of focal length 420 vs. 500, but you gain 2 stops and the weight is considerably less.

[nrohrbacker]

I have the 7d, 500/4 and the 300/2.8 (all v1). I recently got the MKIV for better ISO, IQ and speed. It does all of these better than the 7d, you will not be disappointed. As forthe lens, I used to have the 400/5.6. I went for the 300/2.8, then got the 500 for even more reach. All of these are used handheld. Once I got the bigger lenses, I never used the 400 again. In good light any combo of the above will very well ( think SoCal light). When the light goes bad, the MKIV will prove better. It comes down to how close do you get to your subject. Reach is always better. With the MKiV and the 500, this is IT. If cannot get great pictures with this combo, you need more practice, better technique, etc. Good luck !

[Charles Glatzer]

The new camera will make the biggest difference in overall image IQ. Next purchase will be the longer lens. You can purchase a used 500 for less than the new 300.

Chas

[Phil Richardson]

Thank you all for your comments. Charles, I will give some more thought to the camera first option. Your statements are directly to my questions, thank you. And I know you have a wealth of experience you are speaking from. I'm hearing from all of you there is a big difference between the 7D and the 1D4/5DIII option. I guess it is surprising to me that it is a better first step than the lens. Nrohrbacker, it was very nice to hear your personal upgrade experience. On the lens issue, I know many think the 500 is the ideal bird lens. It seems like two stops advantage from the IS and one stop on the opening (for ver 1) is a big advantage over the 400 5.6 for improving ISO numbers. My thinking right now is that I need a 300 for air travel and a 500 for local auto travel (where it can be easily transported). My biggest concern with air travel is what to do with a big lens (ie 500mm) at the times it is not in use. If I am touring, I feel like I have to carry it with me for security, rather than leaving it in a hotel room.

[Chris Cooke]

Phil what no one seems to have mentioned is that with the New firmware 1.2.1 the 5D MKIII will auto focus at f/8 with the centre point and the 4 assist points and when I put the 1.4X Con. on my 400 f/5.6 a lens that Artie put me on to many years ago and a lens that when used well is wonderful and even though my IDMKIII and IDMKIV both focused at f/8 the 5DMKIII focused way faster and the focus system on the 5D is on par with my IDX plus the ISO ability of the 5D is way superior to all the other Canons except the IDX as for IS, despite advice to the contrary I leave mine off unless needed and panning with the 400 f/5.6 is a breeze. I use the 2XKenko on my 500 f/4 series 1 with the 5DMKIII and have no problems hand holding that combo. Best of luck Mate which ever way you go.

[Dan Brown]

All great suggestions. I would bite the bullet and use a tripod! I know it is not mobile but for those conditions, particularly with stationary birds, your current equipment would yield better results at the lower iso's and SS's! And this is the least $$$$ solution. IMHO:S3:

[Phil Richardson]

Chris, good to get your personal experience with the equipment. You have quite an inventory! Dan, thanks for weighing in and for the suggestion. I'm wondering if a monopod would do the job. Never used one myself yet. But I like the portability advantage.

[Diane Miller]

It's not what you're asking, but one thing nobody mentioned is the additional help in some situations from a flash and Better Beamer. Think 1/8000 and up (depending on power needed) for shutter speed.

But if you go to High Speed Sync you lose power (reach) and effective shutter speed. The flash fires a sequence of lower power (shorter duration) bursts to cover the time the shutter is open. (Probably a better explanation online.)

[Chris Cooke]

Phill I always carry a Monopod with me as I use it as a heavy duty walking stick (I have two legs full of Titanium and Surgical Stainless Steel "M/Bike accidents") so the monopod does double duty. I tried using a Ball Head on the Mono, total disaster. Have you considered the cheaper alternative, such as the 300 f/4L IS + the 400 f/5.6 + 1.4XKenko + 2X Kenko + 5DMKIII. The 300 + Kenko 2X = 600mm f/8 with IS + AF on the 5DMKIII and 400 f/5.j + Kenko 1.4X = 560mm f/8 very light and sharp. Both the 300 f/4 IS and the 400 f/5.6 are extremely sharp lenses look them up on Fredmiranda, the 300 has the added advantage of having a very close Min focus, I add some macro tubes and you have a great "Macro" lens for critters that are hard to get close to.

I love my 500 f/4 IS but in truth I get a LOT more use out of the 300 and 400 with extenders and the 5DMKIII. When I am photographing animals in the wilds of Australia I carry the 300 f/4 IS, the 400 f/5.6, the 70-200 f/4IS, the Kenko 1.4X Con and 2X Con my 7D and 5DMKIII and they all fit into my light back pack along with my light and very fast solid state Asus Laptop loaded with Breeze Browser Pro so I can cull on the run.

I am three score and three years old so my system gives me plenty bang with light weight and I will frequently take up to 4000 Images a day, carrying the 500 where I get to would require that I was met by an Ambulance at the end of the day.

[Dan Brown]

Chris, good to get your personal experience with the equipment. You have quite an inventory! Dan, thanks for weighing in and for the suggestion. I'm wondering if a monopod would do the job. Never used one myself yet. But I like the portability advantage.Phil. On two seperate trips to Costa Rica, first, I used a monopod and a better beamer for fill. It worked ok but I wanted more than it could do for me. The second trip I used a tripod and a better beamer for fill also and I wouldn't go again without the tripod. With the tripod in tow, you can also do some slow SS scenics, HDR's and macro if you want. I wouldn't rely on the BB to much, just for fill unless you are in the real dark jungle or night time.

[Phil Richardson]

Hi Diane. I have tried flash with birds a few times in the past and need a lot more practice. I recently got the Better Beamer, but haven't used it yet. I usually blow out highlights. But in these very low light situations it has the potential for getting an usable image. Again, need lots more practice to just give that kiss of light. Chris, that's quite a system you have. Appreciate the detailed explanation, and the feedback on the monopod. I know what you mean about the 500mm. If I get it, I need to be able to carry it all day. I think I can do it if I am birding all day, but concerned about the times I would bird part day and then go on to tour and sight-see, having to deal with it. Dan, thank you very much for the added comments. I don't have a CF tripod, nor a good head, but it would be cheap compared to the lens/camera options. I have also never travelled with a tripod. Sounds like I need to experiment more with it locally to refine my technique and figure out a way to travel with it. Interesting to hear that Costa Rica needs that type of assist.

[Doug Brown]

I do quite a bit of rain forest photography in Costa Rica, and I would like to add that for most perched birds your shutter speed is excessive. With good technique, some fill flash, and preferably a tripod, 1/160 or slower will get you sharp frames. That change alone will save you several stops of ISO. Not that I'm arguing against upgrading your gear.

[Marina Scarr]

I agree with Chas and Doug. If you are going to make a change, going to a 1D4 would be the best bet. However, Doug makes a very good point that your speed could be lowered considerably for stationary birds and that coupled with adding flash could well solve your problem. The next step would be learning to properly use your flash.

[Charles Glatzer]

I agree with Chas and Doug. If you are going to make a change, going to a 1D4 would be the best bet. However, Doug makes a very good point that your speed could be lowered considerably for stationary birds and that coupled with adding flash could well solve your problem. The next step would be learning to properly use your flash.


A chef does not become a better cook with new pots. New gear will open new horizons, but it will not make you a better photographer.
The camera will increase your image quality, with a longer lens making the subject bigger in the frame...the rest is up to you.

[Phil Richardson]

Thanks everyone. So great to hear from so many of the seasoned experts on the forum. Doug, Marina and Charles, I highly respect all of your opinions. Thanks for sharing. I've been shooting birds for a little over a year (some 40k single click images). I have fiercely resisted monopod, tripod, flash. I just love the freedom and light weight of handholding. And I know I am conservative with my 1/640 and 1/800 for handholding on a 1.6 crop with a 400. This recent experience in Taiwan awakened me about low light work. I need to do something because I plan to go back. I have heeded the online advice in the past of trying to figure out where your present equipment is failing you before making changes. I had thought I was very happy with my current setup. After that trip, I am not. You have all given me some good tips. I have a little time before the next trip, so I will be making some changes based on your advice. As I said in my original post, there are many threads already online about 1D4 vs. 5DIII and 300 2.8 w extenders vs 500 4.0 so I appreciate we didn't get diverted into those discussions. Thanks to all.

[Roger Clark]

Hello Phil,

Some comments. Collecting light is the key to photography, and especially so in low light situations. Changing the camera body does not change the amount of light collected. Upgrading bodies has other benefits (e.g. faster AF, faster frame rate), but not any significant improvement in light sensitivity. So if you can only change one thing, camera or lens, only by getting a larger lens will you improve light collection. The 7D is a great low light camera with pixel sensitivity very close to the 1DIV, 5D3 and 1DX, so changing to a newer body will not help light collection. I have a new series of articles that explains this. The third in the series directly addresses your question, but read the first two before the third:

Exposure and Digital Cameras, Part 1
http://www.clarkvision.com/articles/exposure/

Exposure and Digital Cameras, Part 2: Low Light Photography:
When f/ratio Does not Tell the Whole Story
http://www.clarkvision.com/articles/low.light.photography.and.f-ratios/

Exposure and Digital Cameras, Part 3:
Low Light Capability and Upgrades: Digital Camera or Lens Upgrade?
http://www.clarkvision.com/articles/exposure.and.upgrades/

Your present set up with a non IS 400 mm: your exposure times were appropriate for hand holding and going slower would likely have shown camera shake. Low cost solutions include changing to an IS lens so you can hand hold at lower shutter speeds or use a tripod. the 300 f/4 L IS would give about 2 stops longer exposure, thus drop your ISO 2 stops hand holding. The longer exposure collects more light so your perceived noise would be lower. The 400 f/5.6 lens has a clear aperture of 71 mm, the 300 mm f/4 has 75 mm diameter lens, so collects slightly more light. But a 400 f/4 with a 100 mm diameter aperture collects 100/71 squared = 2x more light from a subject in the frame. A 300 f/2.8 has a 107 mm diameter aperture so collects 2.3x more light. A 500 f/4 has 125 mm diameter aperture and would collects 3.1x more light than the 400 f/4.

I currently have a 7D, 1DIV, and 5D2, along with 300 f/4 L IS, 300 f/2.8, and 500 f/4. For low light work, I take the 300 f/2.8, 7D, and 1dIV.

Next in the series will be exposure and the inverse square law.

Roger

[arash_hazeghi]

Hi Phil,

I agree with Marina, Chas and Doug. The 7D low light performance is poor, if you want better quality images a 5D3 or a MK4 is your best choice, that said do explore the possibility of tripod / flash with slower shutter speeds first.

[Roger Clark]

The 7D low light performance is poor,.

This is a common misconception. The usual reason for the misconception is people change some other parameter and attribute a poor response to pixel size. I've attached two figures to illustrate the 7D and low light performance. Three images, one each from a 7D, 1DIV, and 5D2. One set at original pixel size and the second rescaled to the same subject size. Both tell the same story. Which camera shows the fainter and more stars? The 7D(!!!!) by a small amount. The 5d2 with the largest pixels is the distant 3rd. Details on these images, how they were produced (all with the same lens, same exposure time, same ISO), what it means and why are given at:
http://www.clarkvision.com/articles/nightscapes/

Roger

[Loi Nguyen]

Phil, if I were you I would spend the $ on lens first, camera later, and get a tripod for the Taiwan trip. I started out on a T3i and a sigma 18-250mm, and then upgraded to a 5D3 and the 300F2/8 I IS + TCs, but the biggest difference in my bird photo didn't come until I got my hands on the 500f4 II. Not saying good photos cannot be taken with less expensive gear (we have plenty of evidence here with folks taking fantastic bird photos with gear taht cost a fraction of the 500f4 II), but I think until you put your hands on a super-tele, you don't really quite appreciate the IQ it will bring you. I think that is the biggest bang for your bucks. Loi

[arash_hazeghi]

Roger,

I have made it crystal clear in the past that I strongly disagree with your theories. IMO they are incorrect and misleading.

You can argue that 7D is a better low light camera than the 1DX and spend years writing books about it but this issues has been previously discussed to death here and everyone's POV is clear.

I don't see the need to bring up this issue yet again. You made your recommendation and I made mine, to each his own.

[John Chardine]

But if there's a widely held misconception out there, surely the last thing you would do is drop it. I certainly wouldn't. The above example Roger gives appears to me as tangible, visual evidence rather than opinion based on uncontrolled, anecdotal observations.

And BTW, I don't see any reference to the performance of Canon's 1Dx above, but maybe I missed it.

[arash_hazeghi]

But if there's a widely held misconception out there, surely the last thing you would do is drop it. I certainly wouldn't. The above example Roger gives appears to me as tangible, visual evidence rather than opinion based on uncontrolled, anecdotal observations.

And BTW, I don't see any reference to the performance of Canon's 1Dx above, but maybe I missed it.

reference to 1Dx is in pane 20


IMO there is no "wide" misconception just difference in opinion and judgement stemming from one person's unorthodox theories.

I don't really see the connection between a photo of a far star with lots purple fringing, loads of color noise and zero detail with avian photography. IMO it is bizarre and funny, rather than tangible evidence.

we cannot preach our theories as absolute fact and try to force other people to agree with them. It's like preaching a religion. It is not productive IMO.

We have had all of these discussions before didn't we? It was just a few months ago.

I don't think they are being brought up again in good faith. I am out, but if you guys want to continue the debate, I think it's best to open a separate thread IMO.

[John Chardine]

Thanks. I see the reference Roger made to the 1Dx but the nice graphic comparison he gives above has absolutely nothing to do with the 1Dx so reference you made to it Arash, is what is called a Red Herring. Anyway, I digress. Even a mere biologist like myself can see that a star field is a good model image to show sensitivity and noise characteristics of a camera. If it's not a good model for what we do in broad daylight then I would appreciate being enlightened as to why.

[arash_hazeghi]

Even a mere biologist like myself can see that a star field is a good model image to show sensitivity and noise characteristics of a camera. If it's not a good model for what we do in broad daylight then I would appreciate being enlightened as to why.

All has been discussed before to death and I have indicated why these analysis are misleading IMO. Just do a search.

this isn't new John, your position is clear to me. You have already made your mind that you want to agree/support whatever Roger preaches in sole opposition to my comments. If you take your 1D4 and 7D out for a day of shoot it is not hard to see which one comes out better. There are thousands of reviews online too. easy to read and see.

I cannot really understand your motivation here. You first recommended Phil switch to a 5D3 in pane 2, which was logical and great but then changed your mind quickly(?) I think there is something else going on behind the scene here :w3 I am not taking the bait and leaving discussion.

Good luck.

To the OP, If you do upgrade to a 5D3 or 1D4, once you see the improvement please come back and share your findings with us in this thread.

[John Chardine]

I'm a scientist (retired admittedly) and make decisions based on evidence. I don't follow anyone blindly, as you seem to suggest.

The thread has taken some twists and turns, as often happens in conversations. Nothing is going on behind the scenes as you suggest. Phil seemed to be comparing the 1DIV and the 5DIII and that is the question to which I gave my opinion (right or wrong). The turn in the thread came in pane 21 with the "broken record" idea that the 7D has poor low-light performance, which despite anecdotal support, appears to lack evidence. My subsequent comments addressed that "turn" in the thread and are not relevant to my original opinion given to Phil.

[Roger Clark]

Roger,

I have made it crystal clear in the past that I strongly disagree with your theories. IMO they are incorrect and misleading.

You can argue that 7D is a better low light camera than the 1DX and spend years writing books about it but this issues has been previously discussed to death here and everyone's POV is clear.

I don't see the need to bring up this issue yet again. You made your recommendation and I made mine, to each his own.

Wow Arash,
What I present is not simply my theories. It is basic math and physics and standard science in optical systems design. I practice this every day professionally (e.g. with aircraft and spacecraft imaging systems) and have even taught on this subject at the graduate level. Try googling the words:
Etendue imaging light system throughput
and you will find many web sites and pdf papers discussing these concepts. Check the math at http://en.wikipedia.org/wiki/Etendue
I also use this knowledge for all kinds of low light photography, from wildlife to nightscapes. Yes, math and physics works quite well.

Regarding imaginng star fields, a star test is the most stringent test of an optical system Star images will show defects that you will never see in a bird photo. Pretty much all the stars in the image I presented have their intensity calibrated, so one can in principle determine to within a few percent the relative sensitivities of the cameras. And we see that the 1D4 and 7D are very close, with the 5D2 trailing a little.

If the 7D had such poor low light performance, it would not show fainter stars than the 1D4 and 5D2 cameras. Stars are a great test of sensitivity. I also have data for the 1DX and 5D3. With the exception of the older generation 5D2, the 1D4, 7D, 5D3, and 1DX all have very similar sensitivities. Where the 7D and 5D3 sensors fall short relative to the 1D4 and 1DX is in greater fixed pattern noise at lower ISOs (less than about 1600). It is clear and proven by basic math and physics that when the sensors are so close, the key to light gathering and low light performance is the lens.

The main issue in correct comparisons of sensitivity and the 7D perception on the web is in equalizing Etendue, which people routinely fail to do. And no, it is not a theory.

Roger

[arash_hazeghi]

I'm a scientist (retired admittedly) and make decisions based on evidence. I don't follow anyone blindly, as you seem to suggest.

The thread has taken some twists and turns, as often happens in conversations. Nothing is going on behind the scenes as you suggest. Phil seemed to be comparing the 1DIV and the 5DIII and that is the question to which I gave my opinion (right or wrong). The turn in the thread came in pane 21 with the "broken record" idea that the 7D has poor low-light performance, which despite anecdotal support, appears to lack evidence. My subsequent comments addressed that "turn" in the thread and are not relevant to my original opinion given to Phil.


Sorry, but I don't buy that. It is clear to me what your intention was in this thread. It is not the first time. I don't think it was coincidence that you and Roger showed up at the same time on this thread and only after I posted. I always had great respect for you, despite the fact we did not agree on some topics. All Canadians that I have met are extraordinary nice people!


Speaking of science, I have more patents in image sensor technology than anyone else on this forum. My record is not floating in theories and B-S irrelevant analysis, 1/2 is in the patent office and the rest is in peer-reviewed publications and some in the camera you have in your hand. My photography record is also in the photos that I make, good or bad at least I take some photos of birds. At least I own the gear I talk about.

My goals is to help people with photography, not winning arguments or intimidating people with stuff they don't understand in order to establish myself as the "absolute" authority in the field of theoretical photography. I am not in need of attention. Neither am I jealous at someone else to try to discredit them.

nuff said.

[Dan Brown]

Help! Super Mods! which expert does the hobbist believe?

[Bill Jobes]

Scanning the Web, I've come across lots of evidence that there are two camps on the 7D low light performance question.

While Internet chatter on the matter seems inconclusive, much of it on both sides is the product of personal opinions and perceptions.

But to my eyes, the photo panels posted above by Roger are convincing evidence that the 7D clearly out-performed the other two bodies with regard to low-light handling.

[brian simpson]

Hmmm ,Maybe their both right..I have a 7d that I find has high noise from iso 200 to 1600, I also have a D700 that has very little noise from 200 to 1600. Ime wondering maybe the D700 better for low iso and closer subjects.And D7 for higher iso more pixels on subject for subjects further away...? Phil I love my 400.5.6 but for lower light I really need a 400.f4

[Phil Richardson]

Thanks again to all for taking the time to express your opinions and share your wealth of experience. I didn't realize it when I originally posted, but it is obviously a very controversial issue. I will be renting some gear over the next few months and doing further experimenting to try to make my own evaluation. I have some time before I will be going on a trip where I will be on a fixed schedule and anxious to get quality results under what could include very low light conditions. Locally I can deal with the present limitations of my gear. Everyone seems to be polarized on their positions, so coming back with my lay opinions will not be of substantial value to resolving this. The discussion has definitely helped me a lot, and hopefully others as well.

[Roger Clark]

I have a 7d that I find has high noise from iso 200 to 1600, I also have a D700 that has very little noise from 200 to 1600. Ime wondering maybe the D700 better for low iso and closer subjects.And D7 for higher iso more pixels on subject for subjects further away...? Phil I love my 400.5.6 but for lower light I really need a 400.f4

<big><tt>
Brian,
Excellent observations. Etendue and the concepts I have been discussing exactly show what is happening and why.

The 7D has 4.3 micron pixels while the D700 has 8.45 micron pixels.
This translates to pixel areas of 18.5 square mm for the 7D
and 71.4 square mm for an area ratio (D700 pixel area/7D pixel area)
of 3.86, or about 2 stops.

So, for the same sensor sensitivity (which will be very close, probably
within 10 percent or so), a D700 will collect almost 2 stops more
light per pixel from the same lens and same exposure time and f/ratio (note, this
is independent of ISO; remember ISO does not change sensitivity).

But the D700, with its larger pixels, has less pixels on the subject,
so the image has less resolution on the subject. Linearly, this would
be 4.3/8.45 = 0.51x fewer pixels with the D700. Area would be 0.26x fewer pixels,
or exactly the same fewer pixels by area as the per pixel area ratio,
and the reduction in light per pixel for the same camera exposure.
It is simple math to sum up the light per pixel to find the total light
from the SUBJECT is the same (7D: 1/4 the light per pixel but 4 times more
pixels).

The bottom line is pixel size directly trades resolution (pixels
on subject) for more light per pixel. This is what we perceive
as lower noise in the images from the camera with larger pixels.

But if one's goal is to have the same pixels on subject with the D700
as with then 7D, the solution (which will be close, within about
4%) is to add a 2X TC on the lens when on the D700. But what do you
do regarding exposure when you add a 2X TC? Either 1) increase ISO two
stops, or 2) increase exposure time by two stops, or #3 open the aperture by
2 stops (if possible). If #1, we get a noisier image (because
ISO does not increase sensitivity), and we did not change the true exposure.
#2 and #3 increases exposure so improves the signal-to-noise ratio.

Now, the 7D with the same lens as used above gets the pixels on the subject
that the d700 needed a 2X TC to achieve. Functionally, the smaller
pixels of the 7D are the same angular size as the pixels for the D700
using a 2x TC on the same lens. Same pixels on subject. Same depth
of field. Same light per pixel. This is what Etendue is: the Etendue
of the two cameras are equal. But by the way the camera manufacturers
have defined camera exposure, the meter says use the same exposure
on the subject that the D700 with no TC says to use on the subject.
But we see this results in less exposure per pixel and more noise with the 7D.

To expose the 7D image like that with D700 and the 2x TC, simply treat
the 7D like is has a built in 2x TC (compared to the D700 pixels),
and thus increase exposure by two stops (longer exposure time or
larger (faster) aperture). This then equalizes the Etendue, the
pixels on subject, the light per pixel and the exposure. Then the
noise will appear the same.

So try this to prove the concept: Find a static scene and image
it with the 7D. Next use the same lens on the D700 (assuming you have
the same focal length and f/ratio lenses for the two cameras). and set the
f/ratio the same as you used on the 7D (let's say it is f/4). Now add a 2X TC
(the f/ratio will now change 2 stops, e.g. to f/8) and expose manually
with the same exposure time as on the 7D. The signal-to-noise ratio
will be the same in the 7D and D700 images.

The bottom line is understanding Etendue enables one to manage
true exposure on the subject, as well as camera exposure to achieve
the noise one wants in one's images. If you have cameras with different
sized pixels, and if you want the same noise appearance, treat the
cameras with smaller pixels as if they had TCs.

Roger</tt></big>

[Roger Clark]

One more example. After my post last night, I forgot to mention there is yet another way to approach the noise difference between large and small pixels. In last night's post, I talked about adding a 2x TC to the D700 camera to bring the pixels on subject to be the same as in D700 images. But another way to reduce the apparent noise in the 7D images is to average 2x2 pixels. This brings the pixel size to almost exactly the same as that for the D700. Then the apparent noise between the two cameras will be the same.

In the Etendue explanation, the A*omega product is equalzed. The A is the lens area and the omega is the angular area of the pixel. One can manage the angular area of the pixel by changing focal length, or changing pixel size. If changing pixel size, then there is no difference in signal to noise ratio whether using a different camera with different sized pixels, or one post processes and adds pixels together. By using the same lens, the A (lens area) is the same, and we change omega by changing cameras, focal length or adding pixels together. (Photoshop is behind the times and doesn't add pixels.) There is another side effect of adding pixels together, and that is the resulting image has sharper pixel to pixel contrast (this was shown in one of the original links I gave: http://www.clarkvision.com/articles/low.light.photography.and.f-ratios/

So adding pixels together with the 7D in 2x2 averages not only produces apparent noise equal to that from the D700, the 7D image will appear slightly sharper. This, of course, assumes the subject fits in the frame of the 7D and the same aperture diameter lens and same focal length is used on both cameras.

Attached is another example using a 7D at ISO 6400, which produces a quite noisy image. Compare that to the 5DII, with its larger pixels produces an image with less apparent noise, but lower spatial resolution, And then compare to the 7D with pixels averaged 2x2: pretty clean image in comparison. So the 2x2 image simply has the omega in the A*omega equation made larger (by 4x or 2 stops). Note that the TOTAL light from the subject is the same for the original 7D image and the 2x2-pixel averaged image.

Again Etendue explains all the situations. Understand Etendue and manage noise, resolution and exposure better and how they trade in real world imaging,

Roger

[brian simpson]

Thankyou Roger for going to such lengths to explain this in such a detailed and easy to follow way with, examples,photos,and references

[Daniel Cadieux]

There is no question that the 1D4, 5DIII, and 1DX are better cameras (and they are priced as such!), but there is no reason you couldn't get consistently good results with the 7D. Yes I do not like to push it past ISO 1600, but at that setting, from what you describe, you would have had shutter speeds of 1/320s. and 1/400s...manageable with good handholding techniques (or tripod / monopod). Even 1/160s. and 1/200s. @ ISO 800 can be achieved very well. Ceratinly an "IS" lens would help. Either way, new camera or new lens you will be able to push things higher but in the meantime the 7D and 400mm f/5.6 combo is quite capable.

[Graeme Sheppard]

I'm not a pro level photographer, but I have experience with the 7d and the 400L and 70-300L IS lenses. Most my photos are in low light forest/jungle.

I also dislike a tripod, monopod and flash, so clearly I compromise on absolute image quality.

With all that, the biggest improvement if you are only going to change camera or lens is to get an IS lens. Next is debatable perhaps between wider aperture and better noise control, but these don't come close to the advantage of IS.

Of course, if you top quality, use a tripod with your current setup and you'll be fine.

By the way, I use my 7d and 70-300L at f5.6, slowest shutter speed I can get and ISO usually between 800 and 3200. The images turn out just fine for my purposes (with some selective NR if needed).

[Andre van As]

Hi Roger
The reason I am on this thread is that I was concerned at not seeing your name on the Scientific Forum moderators and wondered if you were still participating and providing balanced, scientific and well supported information on the physics of photography.
Like John Chardine I am a retired scientist and I enjoy your informative and well reasoned tutorials. So I went to Wikipedia for a simple definition of Edendue - "characterizes how "spread out" the light is in area and angle". This definition is followed by mind boggling mathematical proofs way beyond my comprehension.

However to get back to practicalities I deduce - and please correct me if I am wrong -
1. If one has a sensor with a finite area then the sensor with more pixels in that area will have a greater resolving capability than than a sensor of the same area with fewer pixels? Hence the smaller the pixel pitch the greater the resolution for and equal number of photons falling on the two hypothetically equal sensor areas. This is what you clearly demonstrated in pane #22
2. So if we have two systems with approximately the same pixel size (~6um - 6.4um) and one has 50 MP (6132x8176 pixels) in a sensor area of 36.8x49.1 mm and another has
22.1MP: (5760 x 3840) in a sensor area of (cannot put my finger in the 5DIII specs right away and I am presuming it is smaller than the area of the 50 MP example) then given the same relative magnification of a subject on the two sensors the former will have a higher resolution?

Kind regards

Andre