Canon Elan 7 autofocus accuracy?

[dugrant153]

Hey folks,
I'm trying to determine if either my my Elan7 has been misfocusing or the Canon EF 50mm F1.4 that I have on it is not working properly. Lately I've done a few shots with it and found that it has been missing focus on some shots and then absolutely nailing others. The conditions vary greatly but overall I'm finding that either the shots are nailed completely OR they are off by just a smidge. I'm usually shooting from F1.4 - F2.8.

So overall, my question is: Is the Elan7 supposed to be pretty accurate for focusing? like at least 90% of the time (in varying and sometimes difficult conditions - indoors?).
And I've also heard things about the EF 50mm F1.4 being a lens that doesn't last. I've had mine for 3-4 years and used it a lot.

 

[koraks]

Well, interestingly, I've been having the same issue, it seems. Focus with this combination (EOS30/50-1.4) seems to be more miss than hit in my case. I checked focus with the camera on a tripod and a ground glass in the film plane, but found no problem with alignment. Also tried to improve film flatness by readjusting the film pressure plate, but I'm not sure if it has helped any. The issue seems to be front focus in my instance, with focus generally being an inch or so in front of the actual focus point at short distances. At long distances (infinity), the issue is obviously quite severe, with focus being a long distance in front of infinity. Unfortunately, I can't offer any advice, but can only assert that I'm experiencing the same problem. I can't exclude user incompetence, but this is so far the only combination that is giving me somewhat consistent focus problems...

 

[Rowreidr]

This is a known issue with that lens. Pressure on the front of the lens, i.e. drop or even just putting the camera lens side down with the lens not at infinity (the front all the way retracted), can be transmitted into the lens and affect some of the focusing parts. I had to send it mine in to Canon to be fixed/recalibrated, and was told to put the hood on and NEVER take it off. There are videos which go through the disassembly and repair on the tube and I remember there was an official Canon recall for focusing a few years ago,

 

[Anon Ymous]

This is a known issue with that lens. Pressure on the front of the lens, i.e. drop or even just putting the camera lens side down with the lens not at infinity (the front all the way retracted), can be transmitted into the lens and affect some of the focusing parts. I had to send it mine in to Canon to be fixed/recalibrated, and was told to put the hood on and NEVER take it off. There are videos which go through the disassembly and repair on the tube and I remember there was an official Canon recall for focusing a few years ago,

This doesn't explain why I have exactly the same erratic AF performance with the same camera, but with the 50mm STM and 100mm macro lens. It has to be a camera issue.

 

[koraks]

This is a known issue with that lens. Pressure on the front of the lens, i.e. drop or even just putting the camera lens side down with the lens not at infinity (the front all the way retracted), can be transmitted into the lens and affect some of the focusing parts. I had to send it mine in to Canon to be fixed/recalibrated, and was told to put the hood on and NEVER take it off. There are videos which go through the disassembly and repair on the tube and I remember there was an official Canon recall for focusing a few years ago,

I dont get how the same lens can focus perfectly on the ground glass and on the film plane at the same time when checked with the back open, but not with film in the camera.
Not saying it can't be related in any way to mechanical defects in the lens, but 5he evidence just won't add up to this hypothesis.

 

[Rowreidr]

Multiple lenses does sound like a camera issue. My point is that the 50mm f/1.4 USM has a somewhat known defect with the focusing mechanism which in my own experience resulted in multiple issues with focusing (focusing plane was off and miscentered), despite microfocus adjusting available on several digital EOS. Common enough that there are multiple disassembly and repair videos available online.

 

[Rowreidr]

I dont get how the same lens can focus perfectly on the ground glass and on the film plane at the same time when checked with the back open, but not with film in the camera.
Not saying it can't be related in any way to mechanical defects in the lens, but 5he evidence just won't add up to this hypothesis.

I definitely do not have the same experience as you, i.e. I have no idea how one would check focus as the film plane. Take my thoughts with a internet grain of salt, especially since this is mostly based on my nearly 10 year experience with this lens, on digital. Even after my repair, for a misaligned and miscentered focusing plane, I still had to MFA the lens, because of front focus. My interpretation of what was told to me, and as it applies to you, is that the focusing system determines a distance to focusing point, sends the info to the lens, the lens goes to what it thinks is the correct distance, but is off. MFA is a software way of dealing with it, not available on film. I had the option of sending in my body with the lens to Canon to get them "caibrated" to each other and was told to get the hood.

I think Canon intended it to be mediocre built lens with decent optic, leaving enough reasons for anyone who could afford it, to get the f?1.2 L.

 

[koraks]

My interpretation of what was told to me, and as it applies to you, is that the focusing system determines a distance to focusing point, sends the info to the lens, the lens goes to what it thinks is the correct distance, but is off.

Regardless of this being how it works, manual focusing would resolve it if it were an autofocus issue. I get the same problem with manual focus.

 

[koraks]

This is a known issue with that lens. Pressure on the front of the lens, i.e. drop or even just putting the camera lens side down with the lens not at infinity (the front all the way retracted), can be transmitted into the lens and affect some of the focusing parts.

I think I my owe you one. I dug up one of those youtube vids and tool the lens apart. I found that one of the focus tubes had a minor bulge, a fraction of a millimeter - I had to use a piece of sheet glass to verify it was actually there. Knocked it back with a hammer (not kidding) and reassembled the thing. It seems the problem has diminished to the point where I think the lens is within its factory tolerances. At 1.4 coma is pretty bad on this model so it can be hard to verify correct focus, but I just did some enlargements from vision 3 50d test frames shot at 1.4 at different distances and focus now seems to be where I put it. I used AF for these shots so I trust that with MF it should be OK too.

 

[Rowreidr]

I think I my owe you one. I dug up one of those youtube vids and tool the lens apart. I found that one of the focus tubes had a minor bulge, a fraction of a millimeter - I had to use a piece of sheet glass to verify it was actually there. Knocked it back with a hammer (not kidding) and reassembled the thing. It seems the problem has diminished to the point where I think the lens is within its factory tolerances. At 1.4 coma is pretty bad on this model so it can be hard to verify correct focus, but I just did some enlargements from vision 3 50d test frames shot at 1.4 at different distances and focus now seems to be where I put it. I used AF for these shots so I trust that with MF it should be OK too.

Hey, congrats. Glad you were able to figure it out!

 

[dugrant153]

Update: So I tested MY camera with multiple lenses and it seems like the other lenses all focus OK but the EF 50mm F1.4 just had a smidge out on some distances... annoying to say the least. It's a fantastic lens but the build quality isn't there.

 

[koraks]

Hey, congrats. Glad you were able to figure it out!

Let's hope so; I'll have a couple dozen frames to develop later this week and fingers crossed the problem doesn't appear in them - otherwise I'll have to cope with some blurry memories haha