Sharpness ef 300mm L

hello,

For a few months now i have a canon 300mm f4 L. Before i had a sony a200 with sigma 70-300 and i wanted longer reach and much more sharpness. So everyone advised me to buy a canon camera with a 300mm f4. Now i can't get really sharp results. I've tried it with a kenko 1,4 converter, wich should be as good or even better as the canon, but the results are dramatic. lot's of ca and unsharpness. Without it it's quite better but still not sharp. From what i heard, and read in reviews this lens would be razor sharp and almost as sharp as the canon 500mm. Now i can't get that sharpness. It's really frustating. Is it about me or could something be wrong with the lens? For example this picture: http://www.birdphotographers.net/for...ad.php?t=58825 The conditions were good, 5.6 shutter speed was 1/1000e, i was lying on the ground so the camera was supported good, is was on. This picture should be much sharper, right? I already sharpen it up in photoshop. I hope you guys can help me!

p.s excuse me for my english, i'm 16 year and live in holland, got to work some more on the grammar and stuff

Hoi Thijs,

Don't worry you will get sharp images, a few tips:

1) first try getting sharp images without any TC.

2) hold the lens really tight and steady, turn IS ON (mode 1) to minimize shake, choose shutter speed faster than 1/1000sec put your camera in one shot AF and point at a contrasty stationary target like a flower and shoot.

3) if you are still unable to get sharp images put the camera and lens on tripod, lock down and turn off IS. focus on a contrasty target and shoot in self timer mode, if still not sharp then camera/lens may need adjustment.

I see that you have a 30D with practice you should get close to this (shot with a 20D + 300 f/4 IS)

http://www.stanford.edu/%7Eahazeghi/...rait%20low.jpg

BTW, it won't be as sharp as this with the TC, but still sharp enough, plus I would recommend Canon TC over third party. Remember sharp appearance of the subject depends on the focus plain, if the focus is off, even slightly, the image will not look sharp.



Good luck!

... would not use a Kenko converter with that lens, image quality will suffer stick with the Canon !!!

If you have any doubts about the lens test it !! Shoot a target which can be a newspaper under ideal conditions .. tripod, lots of shutter speed. Check on computer Will be sharp.

From the image you showed on the link its hard to tell since you have two birds and they are small. One can not be sharp since it is not within the depth of field of the lens.

Try the test and let us know !!! ... great suggestions by Arash !!!

Thanks for the comments!

You mean like this? f4, 1/500 second, is off, one shot af, tripod, remote control

http://i957.photobucket.com/albums/a...p/_MG_8452.jpg

If your newspaper was flat on a piece on cardboard and you were using a tripod and the camera was at a 90* angle to the newspaper, you have a serious lens problem.. Tape a piece of newspaper to a solid mount, like a piece of cardboard, so it can't move, place your camera on a solid tripod and adjust your camera to the same height as the newspaper, then shoot the test again. If you get the same results, send the lens to Canon for repair..

Dave

Alright, how about this one? one the same heigt as the camera.

http://i957.photobucket.com/albums/a...p/_MG_8459.jpg

Looks good You could try smaller print to check to make sure !!

btw for testing do use more shutter speed so there is no question about movement. You lens seems fine !!!
Next time you go out try without the converter. Even without a converter with the camera crop factor you have an effective focal length of 480mm ... easy to have camera shake !!! .. with the converter is 600 !!!!

Thijs-I would also advocate testing the lens just to put your mind at ease. When I do this I:

1. Tape a bank note to some glass and support upright. There is usually some very fine, almost unreadable print on the note that you can use for critical sharpness assessment.
2. Set camera up on a tripod, level with and perpendicular to that portion of the note you want to photograph.
3. Light the note with flash if possible using a high shutter speed and H-synch. Set mirror lock-up, and the self-timer at 10s. Use a cable release. Set the exposure so the note is well-lit, not dark like the examples above.
4. Evaluate lens wide open and at various f-stops to see any improvement in IQ.
5. Use auto focus with lens initially set to infinity, thereafter "bumping" the shutter release a few times to home-in on the optimum focus point. Also do a set with manual focus to see if your AF is way out. Manual focus is much easier with magnified Live View which I know you don't have.

It is possible that your problem, if you have one, is focus-related and maybe you need to have your lens and body calibrated by Canon. I would try the above method first though.

Thijs,
It is hard to evaluate sharpness at this small size, please post a 100% crop of the RAW file. bank note is a very good target.

Make sure to also check for front and back focus. You may need to do some micro adjustments. My 4/70-200L IS (which is one of Canon's sharpest zoom lenses) had a slight back focus which results in unsharp images. After Canon fixed the lens, everything was fine.

Search the forum for micro adjustments and you will find good information.

I also own that lens and I absolutely love it. It is very fast, even with the 1.4x and wide open at f5.6 (stick with Canon extenders!!!).


Markus

Thanks for the comments. I'll post a 100 % crop later (dom question,but how do you do 100 % in ps) And i will do the other test. Thursday i'm also going to compare it with someone's other 300mm and with the canon extender.

I read about front or backfocus. I don't know how to test that. And micro adjustment was only on the newer canon camera's right? (50d etc, not on 30d)

Quote:

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Originally Posted by thijs broekkamp

Thanks for the comments. I'll post a 100 % crop later (dom question,but how do you do 100 % in ps) And i will do the other test. Thursday i'm also going to compare it with someone's other 300mm and with the canon extender.

I read about front or backfocus. I don't know how to test that. And micro adjustment was only on the newer canon camera's right? (50d etc, not on 30d)

---

Open a photo in photoshop and just use the crop tool to crop an area that appears sharpest, do not resize or change the resolution of the photo.

30D does not have MA feature.

Good luck.

Thijs- Regarding 100% renditions of images- when you look at images on the web, e.g., BPN, you are looking at them at 100%, which means one pixel in the image is rendered with one pixel on your monitor. The key here is that you cannot resample the image at all during the processing stage (in Photoshop- Image->Image size). You have to take your image and just crop it so that it will fit on BPN- 1024 x 800 max. So edit your image from the 30D with your favourite software and simply crop to those dimensions or less, then save, without any resampling in between.

So, is this a 100 % crop?

http://i957.photobucket.com/albums/a...rocentcrop.jpg

And this is the blank note test. I hope i understood it right!

AF with f4:
http://i957.photobucket.com/albums/ae54/thijsbroekkamp/_MG_8462.jpg
AF with f8:
http://i957.photobucket.com/albums/ae54/thijsbroekkamp/_MG_8463.jpg
AF with f16:
http://i957.photobucket.com/albums/ae54/thijsbroekkamp/_MG_8464.jpg
MF with f4:
http://i957.photobucket.com/albums/a...p/_MG_8465.jpg
MF with f8:
http://i957.photobucket.com/albums/a...p/_MG_8466.jpg
MF with f16:
http://i957.photobucket.com/albums/a...p/_MG_8467.jpg

You are close Thijs. First there's no way you can look at an image and say for sure that it is a 100% crop because it depends on if you resampled the image or not beforehand. If you did not resample, just cropped it, the image then we are seeing it at 100%.

In the advice on a good photo target, we should have said a Euro bank note, money, etc. Canadian money has some really small text printed on it to prevent photocopying and forgery. Euros may have something similar. Even if they don't, the bank note will have nice crisp text and lots of detail that you can use to assess sharpness.

In your tests I would up the exposure a bit to get a brighter image. This will be easier to assess.

Alright, i thought a BLANK note!:p

f4
http://i957.photobucket.com/albums/ae54/thijsbroekkamp/_MG_8469.jpg
f8
http://i957.photobucket.com/albums/a...p/_MG_8470.jpg
f16
http://i957.photobucket.com/albums/a...p/_MG_8472.jpg

Quote:

---

Originally Posted by thijs broekkamp

Alright, i thought a BLANK note!:p

f4
http://i957.photobucket.com/albums/ae54/thijsbroekkamp/_MG_8469.jpg
f8
http://i957.photobucket.com/albums/a...p/_MG_8470.jpg
f16
http://i957.photobucket.com/albums/a...p/_MG_8472.jpg

---

Thijs,

First the dollar bill is not flat that's why some parts are sharper at f/4, make sure the note is flat, also post a 100% crop of the bank note as instructed above. BTW don't need to go to f/16, f/4 is best to check focus.

Getting close!!!! from what I see so far your lens has no issues

Thijs,

Do you have a filter on the front of the lens, e.g. a UV or skylight filter? If so try images the dollar with and without the filter.

Roger

I have taken over 100,000 images with the 300mm f/4L IS on my 30Ds and it is as sharp as a tack but like all long primes you need to learn the technique to use it well.

Give it time or give it to Canon.

Alrigh so a other photographer stopped by today to do some test. We tested it with the kenko and his canon 1,4. The canon is better, sharper. He was convinced that without converter everything is fine. He's sharp as he should be. So that's good news, i think i have to give it time like christopher says!

Anyway, thanks for all the help!

p.s he also had his 600mm f4 L with him, amazingly sharp...!

Glad that your lens works fine. Always use the Canon 1.4x when you need it. With proper technique you will get great results.
Yes, the 4/600 is (like the 4/500) an incredibly sharp lens. Maybe one day you can own one.

Markus

Your test samples uploaded are all too dark and lacking contrast. You need to learn to correctly expose and light under controlled circumstances before you can make sharp photos in nature. Also, the birds in the original photo are too distant. Try practicing on tame animals like dogs or ducks first. Get close, bracket exposures, and study the settings on this forum for properly exposed photos!