# Problems with 50 f1.4 & 135 f2.0 on 1.6x crop sensors



## JoaoPedro (Feb 22, 2012)

Hi everyone

Recently I've tested the 50mm f1.4 on a full frame (5Dii) and on a 1.6x crop sensor (T2i/550D) and realized that at f1.4, f1.8 and f2.0 the lens produces a perfectly clear image on full frame but a seriously unusable image on the cropped sensor. Seriously unusable as in severe chromatic aberrations and almost out of focus image at the center (where it was focusing). The 50mm only became usable on the crop body when stopped down to f2.8. 

Has anyone experienced something like this?
Is it a bad copy of the 50 f1.4? (I don't have another at hand to test right away)
And most important: has anyone experienced something like this with a 135L f2.0?

Thanks
Joao


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## Crapking (Feb 22, 2012)

No problems with either lens on either a 7d or 1.3x 1dIV.


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## carlc (Feb 22, 2012)

No problem with the sigma 50mm f1.4 on my 7d. I rented the canon 135mm f2.0 but didn't have a lot of luck. All my fault with a slower shutter speed than I should have used for the focal length resulting in camera shake. I was trying to shoot a dance recital in very low light. Valuable lesson learned.


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## dr croubie (Feb 22, 2012)

So the obvious questions first:
Autofocus or manual focus?
Tripod or handheld?
Is it only the 50/1.4, or has any other lens done this to you?

A good test would be to set up everything on a tripod, manual focus on live-view, take some test shots at a few apertures, then switch camera bodies, and do exactly the same tests (same iso, shutter speed, etc).

There should in theory be no difference between using the same lens on a different camera body, whether it's FF or crop, except if there's an AF-problem, the mount isn't seated properly (both of which will be fixed by using MF in live-view), or something very weird (like the aperture isn't stopping down to the correct value if the contact is dirty.
Sure, crop-sensors have higher pixel-density, so any value of CA (in mm) will show up as more 'pixels' wide, but that shouldn't be the difference between 'perfect' and 'unusable', it should just be 'slightly more noticeable'.


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## neuroanatomist (Feb 22, 2012)

dr croubie said:


> So the obvious questions first:
> Autofocus or manual focus?



+1. Fast primes suffer from longitudinal CA, throughout the frame (unlike lateral CA) and most noticeable in OOF areas (LoCA is aka bokeh fringing). Fast primes shot wide have thin DoF, meaning more OOF areas. If the AF isn't working properly on the APS-C, the results you describe make sense. By 'not working properly' I mean not well calibrated to the T2i body (but a good match to the 5DII). That's the situation that AF microadjustment is designed to correct, but since that feature isn't available on the T2i, sending the lenses to Canon is the only option. 

The way to confirm that's the issue is to use Live View as suggested, either contrast AF (the slow one where the mirror does not flip up) or manually focus at 10x in Live View.


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## dirtcastle (Feb 22, 2012)

With a 50mm f/1.4, I often have issues with Chromatic Aberration on both a 5DII and 40D. I've just come to accept that as a normal part of an extremely fast, and low-priced lens. For me, the solution is to avoid blowouts from f/1.4 to f/2.

I'm hoping a 50mm f/1.2 will have better AF and low CA, at which time I'll switch. I haven't had significant CA problems with my 135mm L on the 5DII, but haven't used it on a crop.


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## JoaoPedro (Feb 22, 2012)

Tripod, ISO 1600, slowest shutter speed 125 (f4 shots) and highest 500 (f1.4).
f1.4 out of focus @ focus point
f1.6 out of focus @ focus point
f1.8 a little bit less out of focus @ focus point
f2.0 terribly out of focus @ focus point
f2.2 starts to be in focus @ focus point
f2.8 in focus @ focus point
f3.2 in focus @ focus point
f4.0 in focus @ focus point

The Canon 50 f1.4 isn't the only lens behaving like this with my 550D (1.6x crop). I once tried the 50 f1.8 and it was similar, hence the reason for not buying it. But both behaved well on the 5Dii! 

All the other lenses I have (16-35L, 100, 24-70L, 70-200L f4) behave perfectly well on both cameras, crop and full frame.

Any guess?


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## gene_can_sing (Feb 22, 2012)

Lenses always work better on crop lenses because it uses the sweet spot, so the images tend to be sharper across the board with lower CAs.

Are you sure it's not a problem with the camera?


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## RedEye (Feb 22, 2012)

I have some trouble getting my t2i to focus with reliability, might be similar in your case.


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## tjc320 (Feb 22, 2012)

RedEye said:


> I have some trouble getting my t2i to focus with reliability, might be similar in your case.



True story. 

Try to find a friend with the same camera to test the lenses on. I have a strong suspicion that it may be the camera's doing. However, you mention chromatic aberration which can only be a lens issue. However, the cropped sensor is essentially zooming into the center of the lens and can cause any lens flaws to become more apparent. 

I suppose you don't have any samples for us to look at?


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## nightbreath (Feb 22, 2012)

I have experienced similar issues, there were 2 separate problems:
1. 50 f/1.4 didn't focus properly on my 7D (front-focus issue, this lens autofocused properly on 400D though) and I sent it to Canon for camera / lens focus adjustments.
2. Camera didn't want to focus on low-contrast subjects (not sure if it is an issue or normal behavior), so I sent the camera to Canon with sample shots. Here's my thread about the issue: http://www.canonrumors.com/forum/index.php/topic,3355.0.html

Before sending your gear anywhere localise the problem and only then send it for repair. I spent few days of testing in different environment to identify what the problems were.


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## Actionpix (Feb 22, 2012)

Canon 5DII has larger pixelsize than the 550D. (Size as 20D). Therefore it is possible problems, first not visible because they fell into one pixel, might become visible when captured on more pixels. (What you get with smaller pixels.)


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## D.Sim (Feb 22, 2012)

if you're taking test shots on a tripod, get good lighting and drop the ISO all the way down. Probably a good idea to take shots using the usual phase detection and some on live view manual/live view contrast detection to compare like neuro has said as well....

I doubt its the lenses - especially if they're working brilliantly on the 5D already. The crop will be taking the shot from the sharpest area of the image circle.

If you can, do a microfocus adjustment (can't remember offhand if its available on the 550D), or in the case you can't, send it in to Canon (with the lenses) to be calibrated.


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## vbi (Feb 22, 2012)

I had a couple of lenses that worked perfectly on my 40D and 5D2 but were very soft on my 7D. Drove me nuts thinking I was getting something wrong until I look into AF microadjustment. Seems my 7D was prone to front focus. Once adjusted everything works flawlessly.

Moral of the story...what works on one camera will not necessarily work as well on another.


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## koolman (Feb 22, 2012)

Thanks for this question and post, as I'm sure the 50 1.4 + crop are a common combination for many of us, including myself. 

I use the 50 1.4 all the time on my 550d for candid portraits, often even at 1.4-1.6 to allow me the fastest shutter speeds. I found that it takes skill to properly nail focus at such a thin DOF, you need something well lit and good contrast such as eyes or other facial feature. Additionally my 550d has a slight front focus, so I use something to nail focus with that is a little further away, like the far eye, etc.

With patience I get good results. If I want super sharp, and have a more controlled environment (the model is willing to sit still) I use live view and manual focus.

You do need to note: The crops cause you to work at a farther working distance then the FF, and this makes nailing focus more challenging, as the eyes for example are smaller and less bold contrasty then closer up.


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## nightbreath (Feb 22, 2012)

koolman said:


> I use the 50 1.4 all the time on my 550d for candid portraits, often even at 1.4-1.6 to allow me the fastest shutter speeds. I found that it takes skill to properly nail focus at such a thin DOF, you need something well lit and good contrast such as eyes or other facial feature. Additionally my 550d has a slight front focus, so I use something to nail focus with that is a little further away, like the far eye, etc.



I have the same issue with fast aperture primes on my 7D, so I sent the camera to Canon. I'm a wedding photographer, so I don't often have time to check whether the last shot is in focus, so I'd better have camera not confirming focus rather than front-focusing.

I'll get my camera in a week or so, interesting to see if they change something in focusing mechanism.

P.S. I found Live View "contrast detection" extremely precise comparing to default "phace detect".


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## neuroanatomist (Feb 22, 2012)

JoaoPedro said:


> Tripod, ISO 1600, slowest shutter speed 125 (f4 shots) and highest 500 (f1.4).
> f1.4 out of focus @ focus point
> f1.6 out of focus @ focus point
> f1.8 a little bit less out of focus @ focus point
> ...



Let's try again: *Are you using regular/non-Live View autofocus for the shots above?*


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## DBCdp (Feb 22, 2012)

Hey Joao, same problem here. I bought Reikan's FoCal and set about to get all my lenses spot on with both my 5D MkII and my 7D. Everything BUT the 50 1.4 worked out perfectly. While it set up and functions properly on the ff camera, on the 7D it's a totally different story! Using phase detect is not a problem at all, but when using LiveView it front focus' about 10" and the intended focal point is totally blown out. Manually dial the lens out to focus, hit the Live View focus button and wham, out of focus again! I tried manually setting microadjustment in many different settings and it made no difference at all. When used at 1.4 it simply will not focus in Live View. I'll do some more testing today and see how it acts when stopped down, see if it mimics your issues.


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## AJ (Feb 22, 2012)

Some lens/body combos don't seem to focus properly.

I have a 17-55/2.8 that focuses way off on my 7D (thank goodness for AF microadjust). The lens focuses just fine on my 400D. My 7D very accurately focuses all of my other lenses. So you can't blame just the lens, body, or sensor size.

My suggestion is to try another copy of the lens or body, use AF micro-adjust, or else send in the combo for calibration.


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## JoaoPedro (Feb 22, 2012)

Thanks for all your answers. I'll try to post some photos here. And I'm considering in taking the camera to Canon Service to see if they detect something wrong. From what I've read, several of us had problems with the 50 f1.4 on crop sensors, it would be about time for Canon to replace that 1993 design.

For those who suggested focusing micro adjustment be advised that the 550D doesn't have that feature. Only 7D and above? I think the 60D doesn't have either.

I'll take the camera and the lens to Canon. I'll then post whatever news I get.
Thanks guys
Joao


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## neuroanatomist (Feb 22, 2012)

DBCdp said:


> Using phase detect is not a problem at all, but when using LiveView it front focus' about 10" and the intended focal point is totally blown out. Manually dial the lens out to focus, hit the Live View focus button and wham, out of focus again! I tried manually setting microadjustment in many different settings and it made no difference at all. When used at 1.4 it simply will not focus in Live View.



AF Microadjustment only affects phase-detect AF, and has no effect on Live View (contrast-detect) AF. I'd suspect a malfunctioning lens in your case, or perhaps it's just the choice of target confusing the camera?



JoaoPedro said:


> For those who suggested focusing micro adjustment be advised that the 550D doesn't have that feature. Only 7D and above? I think the 60D doesn't have either.
> 
> I'll take the camera and the lens to Canon. I'll then post whatever news I get.



From this, I infer that you were using autofocus (although you still haven't definitively answered that question). That's most likely the problem (as was suggested very early in the thread), and since your camera doesn't have AFMA, sendind the lens (and body, most likely) to Canon is the only option.


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## DBCdp (Feb 22, 2012)

Hmmm, I can see that possibility although this lens has hardly ever been used as I don't like it's lack of contrast. Funny thing is, the 5D MkII handled it as expected. The 7D, put on the tripod in the same position and with the same lens and same target, won't do it. Which makes me think it has more to do with the 7D than the lens. Or certainly a combination of both.

I'll try it again and see if I get the same results, and I'll try different targets as well as different apertures.

Will get back with the results.


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## DBCdp (Feb 22, 2012)

Yep, Neuro you're exactly right! Thanks! The target was the issue, when using any real life setting it Live View focus' just fine. I even got the ma fine tuned, but still not really happy with the overall IQ.


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## DBCdp (Feb 22, 2012)

Oh yeah, in the process I got an Error 40!! I was trying to get the ma set and taking a shot, then zooming in on the image...zoomed in and the screen went black! Error 40 on the top screen. Turned it off. Back on...nothing doing. Dropped the battery, put it back in, all is well. What's up with that? Havent had an error in a Canon body since my 20D back in 05!


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## Kernuak (Feb 22, 2012)

DBCdp said:


> Oh yeah, in the process I got an Error 40!! I was trying to get the ma set and taking a shot, then zooming in on the image...zoomed in and the screen went black! Error 40 on the top screen. Turned it off. Back on...nothing doing. Dropped the battery, put it back in, all is well. What's up with that? Havent had an error in a Canon body since my 20D back in 05!



Here's a list of error codes, error 40 is related to power source problems.

http://www.learn.usa.canon.com/resources/articles/2012/eos_error_msgs.shtml


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## DBCdp (Feb 22, 2012)

After getting the ma fine tuned, the lens performs pretty well. Still the low contrast when wide open but I guess that's to be expected. At 5.6 it's definately sharp, sharper than the 7D can handle most likely. 

These 2 pics are using the 7D with the 50 1.4 @ 5.6, ISO auto, aperture priority using the accurate center focus point. In the distant one you can see the buzzard on the fence post, a little over 340' away. Then he flew off and head towards me and I caught him on the wing, with the sharp center point no less! The second is a 100% crop with zero pp, opened in ACR and saved as jpeg.

Oh yeah, did I fail to mention it's 72 degrees and another beautiful day!


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## DBCdp (Feb 22, 2012)

And using the 7D with LiveView through the 50 1.4 @1.4. 

In the fullsize image, the small holes in the vinyl show as well as trees and small detail in the picture. Even though they didn't get it printed to the resolution I gave it to em! The picture is a downsized version of a 42 shot handheld pano taken from just shy of Nogal Peak looking towards Ski Apache, Ruidoso NM. The original is 3.5'x13.5' at 240dpi. Taken with the 7D and 24-105 @105.

Thanks for getting me straight on this one Neuro, I wouldn't have guessed the target itself was the culprit after successfully calibrating my 5DMkII using it. I might actually keep this lens now! lol

Sorry Joao, didn't mean to hijack your thread but want you to know there's hope!

And thanks, Kernuak, don't know why it did that still but it's good to know what it is anyway. I'll keep my eye on it.


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## kdsand (Feb 24, 2012)

I ended up sending a 50 1.4 back 3 months ago similar issue with my 60D. No matter the aperture i had bad auto focus. It was so all over the place I couldn't even narrow it down to front or back. Mounted on a tripod aimed at a stationary target of course. Canon said I got a bad copy.

The 60D doesn't micro adjust nor do any rebels. Micro adjustment is one thing I would have desired but i wrongly assumed the 60D had it. Then again I don't think micro adjust would have solved this issue.


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## D.Sim (Feb 25, 2012)

kdsand said:


> I ended up sending a 50 1.4 back 3 months ago similar issue with my 60D. No matter the aperture i had bad auto focus. It was so all over the place I couldn't even narrow it down to front or back. Mounted on a tripod aimed at a stationary target of course. Canon said I got a bad copy.
> 
> The 60D doesn't micro adjust nor do any rebels. Micro adjustment is one thing I would have desired but i wrongly assumed the 60D had it. Then again I don't think micro adjust would have solved this issue.



If you had a bad copy no micro adjust would have saved you... but then canon would have replaced it if it was under warranty.


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