Advice needed: 400DO with 7D

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10-21-2009, 01:13 PM
Jia Liu

Advice needed: 400DO with 7D

I've got this 400DO lens a few weeks ago, tested it on T1i against 300/2.8IS in my backyard in a controlled manner, the result is very favorable, hence I sold 300 and kept 400DO. Yesterday, 7D finally arrived. I did some quick testing shots around the house, AF seemed spot on. Then I stepped out for some field test, when I looked those pictures 100% on screen, they are not very pleasing. I shot everything handheld with 1/1600s f/5.6 ISO400, and IS mode in either 1 or 2. So if you have some 400DO on 7D images, would you please post some 100% cropped unprocessed RAW? I don't have my images with me right now, will post some tonight if needed.

One side note: when doing controlled test, I noticed that stopping 400DO down to f/5.6 doesn't seem increasing the sharpness, is that normal?

UPDATE:
Tonight, I carefully did the 45 degree ruler focus test (I made something similar to LensAlign Tool), and found my 7D has severe back focus with 400DO. At first glance, it was so bad that I didn't even have confidence that micro-adjustment might be able to correct it. I scratched my head wondering how come it passed my initial AF test. Anyways, I finally settled down with -15 MA with 400DO alone and -14 with 400DO + 1.4xTC. After that, I did the same test on 1DIII, and it's almost spot on, -1 with 400DO and +1 with 400DO + 1.4xTC, so I know it's not the lens to be blamed. Once again, stop down to f/5.6 or f/8 will increase the DOF but not sharpness at all. I will just need another field test to conclude my final verdict on the combo.

MORE UPDATE:
I just stepped outside in my backyard a few minutes ago, what a different the AF adjustment made!
All images below are 100% crop, straight from DPP, with sharpness at 3 as default

Here is before the adjustment, from the first field test
http://www.pbase.com/sapro/image/118591661/original.jpg

Here is from today a few minutes ago
http://www.pbase.com/sapro/image/118591685/original.jpg

And I can get this kind of tracking consistently
http://www.pbase.com/sapro/image/118591710/original.jpg
10-21-2009, 01:21 PM
James Shadle

In Canon DPP can you see what AF sensor was selected?
If so was the sensor on your subject?
James
10-21-2009, 01:32 PM
Vivek Khanzode

Jia

Please put up some images for us to see like Arash did. I am still undecided about the 7D.

-- V
10-21-2009, 01:33 PM
Jia Liu

James, thanks for the reply! Yes, sensor is on the subject.
10-21-2009, 01:34 PM
Jia Liu

Vivek, will do!
10-21-2009, 06:46 PM
Arthur Morris

Quote:

Originally Posted by Jia Liu

I've got this 400DO lens a few weeks ago, tested it on T1i against 300/2.8IS in my backyard in a controlled manner, the result is very favorable, hence I sold 300 and kept 400DO. Yesterday, 7D finally arrived. I did some quick testing shots around the house, AF seemed spot on. Then I stepped out for some field test, when I looked those pictures 100% on screen, they are not very pleasing. I shot everything handheld with 1/1600s f/5.6 ISO400, and IS mode in either 1 or 2. So if you have some 400DO on 7D images, would you please post some 100% cropped unprocessed RAW? I don't have my images with me right now, will post some tonight if needed.

One side note: when doing controlled test, I noticed that stopping 400DO down to f/5.6 doesn't seem increasing the sharpness, is that normal?

Jai, What do you mean by "not pleasing." You need to be specific....
10-21-2009, 06:46 PM
Arthur Morris

Quote:

Originally Posted by Vivek Khanzode

Jia

Please put up some images for us to see like Arash did. I am still undecided about the 7D.

-- V

Yes, let's see some of the images.
10-21-2009, 11:38 PM
Aravind Krishnaswamy

My 400 DO doesn't get any sharper when stopped down to f/5.6.

My 7D should arrive later this week, I'm going to give it a whirl, will let you know how it goes, but yea posting pictures would help.
10-22-2009, 03:52 AM
Jia Liu

I found out that my 7D needs major AF adjustment on 400DO, see the update in first post.

Aravind, thank you for the info on stop down. This is the first lens I have that stopping down doesn't increase sharpness, even Leica APO lenses become sharper when stopping down a little.
10-22-2009, 07:21 AM
Arthur Morris

There is a difference between sharper and having more d-o-f. And I would not expect that the human eye could detect differences in either when switching from f/4 to f/5.6. At 15 feet at f/4 do-f is .1 foot total. At f/5.6 it is .07 feet total. I am thinking that the human eye will not be seeing a difference of .03 feet of d-o-f. Of course, as camera to subject distance increases the differences might be seen by some folks with excellent vision.
10-22-2009, 12:22 PM
Jia Liu

Quote:

Originally Posted by Arthur Morris

There is a difference between sharper and having more d-o-f. And I would not expect that the human eye could detect differences in either when switching from f/4 to f/5.6. At 15 feet at f/4 do-f is .1 foot total. At f/5.6 it is .07 feet total. I am thinking that the human eye will not be seeing a difference of .03 feet of d-o-f. Of course, as camera to subject distance increases the differences might be seen by some folks with excellent vision.

Artie, when do controlled test, increase in DOF and sharpness is quite obvious.
See this image, 300 gets sharper when stopped down, 400 doesn't, or even gets softer at f/5.6
http://www.pbase.com/sapro/image/118584153/original.jpg
10-22-2009, 01:51 PM
arash_hazeghi

Jia,
Are these samples RAW or JPEG?
10-22-2009, 02:14 PM
Jia Liu

Quote:

Originally Posted by arash_hazeghi

Jia,
Are these samples RAW or JPEG?

RAW, zero sharpening, ISO100, tripod, shutter release, manual focus on 10x live view, best one from three takes, I moved camera to get the same FOV.
10-22-2009, 04:19 PM
arash_hazeghi

Quote:

Originally Posted by Jia Liu

RAW, zero sharpening, ISO100, tripod, shutter release, manual focus on 10x live view, best one from three takes, I moved camera to get the same FOV.

Have you tried EOS viewer utility that gives you 100% feed from LV? You can use the fine focus drive feature to precisely adjust focus. At f/2.8 dof is very thin so a slight misfocus even with 10X mag can cause slight softness.
10-22-2009, 04:54 PM
Carl Gandolfo

Someone on a different forum had a similar issue with different lenses and had luck doing the following. Do a hard shutdown - power down and remove both camera batteries (the main battery that powers the camera and the other small flat cell that powers the clock and date). Leave them out for about 25 mins. Place the batteries back into the camera and repower up. Attach your lens and retest.

He found that after doing a hard power down, the lens' focus was then spot on, dead accurate. Not saying it will work with you but it has worked for a few people that tried it.

Worth a shot at least. Let me know what happens.

Carl
10-22-2009, 05:36 PM
Jia Liu

Quote:

Originally Posted by arash_hazeghi

Have you tried EOS viewer utility that gives you 100% feed from LV? You can use the fine focus drive feature to precisely adjust focus. At f/2.8 dof is very thin so a slight misfocus even with 10X mag can cause slight softness.

No, I didn't when I did the test on T1i. I don't have 300/2.8IS any more, so can't repeat the test.
10-22-2009, 05:37 PM
Jia Liu

Quote:

Originally Posted by Carl Gandolfo

Someone on a different forum had a similar issue with different lenses and had luck doing the following. Do a hard shutdown - power down and remove both camera batteries (the main battery that powers the camera and the other small flat cell that powers the clock and date). Leave them out for about 25 mins. Place the batteries back into the camera and repower up. Attach your lens and retest.

He found that after doing a hard power down, the lens' focus was then spot on, dead accurate. Not saying it will work with you but it has worked for a few people that tried it.

Worth a shot at least. Let me know what happens.

Carl

Carl, yes, I read about that, and in fact, that's the first thing I did when I did the AF adjust last night.
10-22-2009, 05:42 PM
Jia Liu

Updated first post with before and after pics.
10-23-2009, 07:45 PM
Arthur Morris

Jia, I am not sure what the images in Pane #1 are intended to show.... They do not seem to match what you wrote.... Sorry to be so confused.

As for the controlled tests, the next controlled test that I do will be my first. I am not saying that at times folks do not have faulty equipment; in my experience sharpness problems are caused 99% of the time by operator error. That is why I suggested the two simple sharpness tests.