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Archive 2012 · 1DS-mk3 sensor alignment
  
 
ben egbert
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p.2 #1 · p.2 #1 · 1DS-mk3 sensor alignment


Exactly my problem. I also had this problem with the Zeiss 15 f2.8. I finally returned it.

I just went out for some landscape tests, still downloading. I purposely used both af center and live view at the left side.

My 24TSE would always get soft on the left side unless I live view focused there. It would be sharp everywhere else. Same for my 17TSE. My 35L and Zeiss 50 f1.4 never had such problems.

I wonder if its sensor related, perhaps the extreme angle of light at the edges? Just a tiny misalignment could have large consequences. I wonder how a 1DX does in this regard? Or a sensor without an AA filter?

Edit. The results are in. If I live view focus at a left edge subject, it is sharper there than when I AF in the center. But the af center is sharper from the center to the right. There is a skew.

All subject distances are about the same distance which is about 200 feet.



Dec 06, 2012 at 10:03 PM
ben egbert
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p.2 #2 · p.2 #2 · 1DS-mk3 sensor alignment


So what now? If I have to manual focus to get it right, I need a new camera with a modern live view system. Or I could just admit defeat like I did with my film camera and sell it all.

Or I could just do what many do and ignore edges and corners. In that case I might as well switch to a crop. I have a 50D, I could sell some of my expensive UWA and get a 10-22 and just use the 50D.

Note this is an admission that I can't manual focus, not blaming my gear.




Dec 07, 2012 at 12:41 AM
Gunzorro
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p.2 #3 · p.2 #3 · 1DS-mk3 sensor alignment


Since you are practically asking for advice:

Have you tried using your tilt mechanism with minute adjustment to sharpen the left side (shift the entire focal plane slightly)?

I think you should consider the 5D3 for its better LCD and AF system.

Don't chuck it all just yet! But the 1Ds3 is pretty poor on the LCD and LV, so it's not doing you any favors.



Dec 07, 2012 at 02:01 AM
ben egbert
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p.2 #4 · p.2 #4 · 1DS-mk3 sensor alignment


I have actually thought about using the tilt to test the theory, but that would not be a practical solution. I will probably try it tomorrow. I no longer have the 24, and the 17 is very sensitive.

I might get a 6D, but the 5D-mk3 is too expensive for only 22 mpixels.

I will tough it out with the 1DS-mk3 until I get so frustrated that I can't stand it anymore. I once in a while get home with a super sharp uwa image. Just a matter of chance however. Nothing I can do on purpose. The soft images are fine once they are reduced for web and if you stand far enough back from a print. Of course longer focal lengths are not such a problem.



Dec 07, 2012 at 02:16 AM
ben egbert
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p.2 #5 · p.2 #5 · 1DS-mk3 sensor alignment


Some other ideas occur to me. I really love UWA, so a 1.6 crop is not a great option. But maybe a 1D-mk4. I would lose some pixels, but would probably gain the uniform image quality I want so badly.

My 14 becomes 18mm. 16 goes to 21 and 17 to 22. Might get better noise and the 1D-mk4 has a better LCD.

Two other thoughts is to send my 1DS-mk3 to a local shop that does astro conversions. I am not sure I want to remove the IR filter, but part of his conversion is to add a heat sink to the sensor, align the sensor to mount and add internal anti reflection. I might also have the AA filter removed.

The heat sink eliminates the amp glow on long exposures. The alignment might solve my soft edge problem (if its really that) and the AA filter removal might make the edges less sensitive to the problem.

I am also going to try a couple other long shots. One is to use all focus points, and the other is to use the left most focus point. I already know that using live view on a left side subject makes an improvement, but this is not always possible because there is not often a good enough target (large high contrast).





Dec 07, 2012 at 05:24 PM
Monito
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p.2 #6 · p.2 #6 · 1DS-mk3 sensor alignment


Removing the AA filter is not going solve or ameliorate your problem.



Dec 07, 2012 at 05:34 PM
ben egbert
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p.2 #7 · p.2 #7 · 1DS-mk3 sensor alignment


Monito wrote:
Removing the AA filter is not going solve or ameliorate your problem.



Probably not. But what will? I could just plan on cropping all my UWA images I guess.



Dec 07, 2012 at 05:42 PM
Jeffrey
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p.2 #8 · p.2 #8 · 1DS-mk3 sensor alignment


Ben, I hope you were not hanging that big ol' 500 from the camera mount, but rather mounting the lens on the tripod and hanging the body off of it.


Dec 07, 2012 at 06:29 PM
ben egbert
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p.2 #9 · p.2 #9 · 1DS-mk3 sensor alignment


I never supported the 500 from the camera on purpose. I was either hand holding or using a Sidekick. I only carried the system over my shoulder while tripod mounted a couple times and decided it was too risky. In that case the camera was still supported by the lens.

But I used this system for a long time and I am sure there were times when the weight of the lens was on the camera for short periods. I used a camera strap as a safety and sometimes had to let it support the system during mount or unmount.

But Canon says it is not out of factory spec. So I suspect I am just wanting more than factory spec.

I will get past this. Every time I get a new lens I learn more about how to focus. Eventually I will get it.








Dec 07, 2012 at 07:05 PM
Mr Joe
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p.2 #10 · p.2 #10 · 1DS-mk3 sensor alignment


The only thing that will solve this problem is getting a camera body and wide angle lens that are both within spec in a complimentary way.

Restated: Even if your camera body is in spec, and your WA lens is in spec, the tolerances to cause uneven sharpness across the frame are so slight that they may occur unless both are in spec in a complimentary way.




Dec 07, 2012 at 08:38 PM
 

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Monito
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p.2 #11 · p.2 #11 · 1DS-mk3 sensor alignment


ben egbert wrote:
Probably not. But what will? I could just plan on cropping all my UWA images I guess.


In your situation, I would try shimming the lens mount yourself on one side or the other. It should not be difficult, I think. Ask Roger Cicala.

Have you tried using somebody else's lens on your camera and your lens on their camera? I know that it is unlikely that your whole set of lenses could be out the same way, but it is worth making those two experiments for confirmation (non-rejection) of your hypothesis.



Dec 07, 2012 at 08:42 PM
ben egbert
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p.2 #12 · p.2 #12 · 1DS-mk3 sensor alignment


+1 on tolerances, as a retired mechanical engineer, I know all about tolerance cancellation and when they add.

On shimming. I just did another test and was very careful on squaring up to the fence. I tried several af, several live view and several all points. Using the left point is a waste of time because it is still too close to the center.

The results were that it was hard to find any better than the others and left right is pretty equal.

Using all points had one shot that choose the sky and tended to be more front focused. Live view was a bit better at the edges and softer at the target. This confirms my poor vision. The AF did better than my LV on the target.

All of them were more equal side to side, but much softer than the center. I am now thinking its just edge softness on this lens and that squaring up the fence is super critical.

Not sure about my other lenses. My 17TSE is sharper on the edge at f4 than this lens is at f11. Its a hard lens to test in that regard. My 24-70 f2.8 mk2 is one of the most consistent AF lenses I have ever owned. So far I have not noticed the left side issue on that lens. But I did with my 24TSE and also my 17TSE. But its hard to duplicate at home with the 17.

This tends to make me think my issue is UWA and that super careful focus is required. Deep DOF on UWA is a two edge sword. It looks close to focus over a range of focus, but it also looks best when perfect.

I need more data to believe what I just found, and I still don't have a solution when I am not shooting a fence.



Edited on Dec 07, 2012 at 09:12 PM · View previous versions



Dec 07, 2012 at 09:09 PM
Jess Edward
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p.2 #13 · p.2 #13 · 1DS-mk3 sensor alignment


I have been having a similar issue with my 5D MkIII but it only happens from time to time. So far in the last month and a half its happened 3 times. I sent it to Canon and explained what was happening and the conditions in which it has always seemed to occur and they told me that there is nothing wrong with my camera and that its simply my own error in focusing.

The person I have been dealing with through email actually told me that the reason this photo is out of focus is because there was not sufficient enough contrast to achieve perfect autofocus every time even though I explained that every photo I took outdoors this day looks this way with the blurred corners and focus point being way in front of the place I actually focused on which was the girls face.

I shot these with a 50mm lens at f2.8. I also shot a lot of other photos with my 24-70 at various focal lengths all with the same issue. Two days after this shoot I photographed an event all day and had no issues but I explained to Canon that its done this multiple times now which makes it very difficult to trust that my camera is going to work when I need it to since I never know whats going to cause it to do this.







It doesnt look so bad when its smaller but at 100% it really shows.




Dec 07, 2012 at 09:11 PM
ben egbert
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p.2 #14 · p.2 #14 · 1DS-mk3 sensor alignment


I can see it. This is really frustrating. I get the same response. Some of my friends claim that live view is more accurate than AF and never use AF for landscape work. This can be a problem even at f8.

But those friends have a 5Dmk2 which has a far better live view than my 1DS-mk3. But this image looks like it needs AF, I assume you were not on a tripod. I have been told that live view AF is the most accurate, but the 1DS-mk3 does not have it. I am pretty sure your 5d-mk3 does however, have you tried that?



Dec 07, 2012 at 09:17 PM
ben egbert
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p.2 #15 · p.2 #15 · 1DS-mk3 sensor alignment


Ok, tested the 17TSE and the 24-70 f2.8 Mk2 while I had the tripod aligned. These don't show any sign of misalignment. But they do demonstrate that Af or AF confirm for the 17TSE is better than live view when I am doing it.

I can get close, but no cigar. Both of these lenses shame the 16-35 on the edges. Maybe I was just shocked at the softness.

I think what I must do is spend a few days practicing live view focus in different light and with low contrast targets. AF is ok on fences, but I know it has trouble in some situations.




Dec 07, 2012 at 10:15 PM
Jess Edward
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p.2 #16 · p.2 #16 · 1DS-mk3 sensor alignment


I was just speaking with someone from Canon. They finally got the hint that Im not just going to let them send me my camera back and they are telling me they can either give me my camera back and I can do tests myself, or I can bring in my lenses and pay a service fee for each one and if they dont find any issues with them I would get my money back.

The guy I was speaking to keeps telling me that of all the images I have sent him the ones with the 24-70 seem to be the worst so he keeps saying it might be an issue with the lens. I have to keep insisting that it doesnt make sense that it would be a lens issue when there is very clearly a problem with the 50mm as well, and only while this issue is happening.

Here is an example of an image I took a few days ago with the same 50mm lens that has no corner blur issues. The rest of the images I took on this day looked fine as well, yet still he insists that he thinks its a lens issue.








Dec 07, 2012 at 10:15 PM
Jess Edward
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p.2 #17 · p.2 #17 · 1DS-mk3 sensor alignment


I keep cross posting between this and my 5D MkIII thread. It appears to be the same issue in both cases only my problem isnt as easy to replicate apparently.


Dec 07, 2012 at 10:18 PM
ben egbert
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p.2 #18 · p.2 #18 · 1DS-mk3 sensor alignment


I think I have a different problem. I am doing mostly landscape work and I have never had an issue above 24mm. I also have this problem with manual focus lenses, In fact more often with MF than with AF lenses. The 16-35 being the exception.





Dec 07, 2012 at 10:30 PM
Jess Edward
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p.2 #19 · p.2 #19 · 1DS-mk3 sensor alignment


It seems so strange to me that Canon just wont admit that there could be an issue with the sensor alignment in either of these cases.


Dec 07, 2012 at 10:43 PM
Hulot
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p.2 #20 · p.2 #20 · 1DS-mk3 sensor alignment


Sorry to say Jess, I think in your case it looks like user error. The focus is on the belly, which is the center AF point, f 2.8 does not provide the DOF you needed here, a flash would help to improve the light quality.
One little step back and your people are OOF. The 50mm needs a stop of 5.6 to cover the full image circle so again, most probaly no problem with your gears.



Dec 07, 2012 at 11:51 PM
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