Canon P focusing issue with 50mm LTM f/1.4

[ckjr23]

Hey all,

I'm new to the forum and semi new to rangefinders so hopefully I don't sound too stupid in this post. I recently got a 50mm f/1.4 and I'm having some focus issues with it. Most of my shots were completely soft, and some even at infinity were out of focus. These shots are on Ilford SFX 200 and I'm shooting mostly around f/5.6-f8. I'm not sure if its the lens (its damn near mint), if I just need to shoot more with it to get the hang of it, or if I need to CLA. I shot a roll on a 35mm lens right after finishing the Ilford roll and all of those shots were fine.

Any insight would be great.

 

[xayraa33]

Do you own any other lens besides the 50mm f 1.4 Canon?

Just to see if it is the lens or the camera is at fault.

What shutter speed did you use and are the images in the negatives out of focus when studied under magnification?

 

[a.noctilux]

Maybe the film in use?

Ilford SFX 200 is a special film, as description from the Ilford site:

"...ILFORD SFX 200 is a medium speed black & white film with extended red sensitivity which makes it the perfect choice for infra-red style images. "

I have and use with pleasure the Canon 1.4/50 with normal film, it's a nice lens.

Enjoy with more "common film" ...

 

[xayraa33]

The Data sheet for that film does mention some focus shift with certain lenses.

https://www.ilfordphoto.com/amfile/...store=ilford_brochure&___from_store=ilford_uk

 

[davhill]

The default task when debugging these issues without dedicated test gear is to switch things around: try the lens in question on another body, and try a similar (i.e. 50mm) lens on this body. It’s useful to know your 35 works fine, but that has greater depth of field so it’s not completely viable as a test. But still.. it does suggest the fault lies in the lens.

The extended red sensitivity of the SFX200 film should not be an issue unless you were using a deep red filter (for dramatic sky) or an IR filter (to capitalize on the IR spectrum). Its normal-light sensitivity should focus in the normal way.

The fact that your lens is ‘mint’ doesn’t mean it’s factory-new. It means only that it’s been well cared for —and was very possibly disassembled for CLA and reassembled without checking its accuracy. Inspection and re-CLA by a competent lens guy seems to be the solution.

 

[Beemermark]

Too me it looks like maybe the wrong (or depleted) developer with (maybe) out of date film. I've had B&W look like that, almost mushy. Wasn't the camera or lens.

 

[ckjr23]

I believe I was around f/5.6 and 1/125 settings in these shots. I have the Canon LTM 50mm f/1.8 and the results with that are infinitely better with that. I shot a second roll (not SFX) this weekend with the f/1.4 and it was just as bad. I'm suspecting it's the lens itself.

Do you own any other lens besides the 50mm f 1.4 Canon?

Just to see if it is the lens or the camera is at fault.

What shutter speed did you use and are the images in the negatives out of focus when studied under magnification?

 

[ckjr23]

I developed a roll right after this one and it was fine. The film was relatively new.

Too me it looks like maybe the wrong (or depleted) developer with (maybe) out of date film. I've had B&W look like that, almost mushy. Wasn't the camera or lens.

 

[ckjr23]

I can possibly test the lens on another body and see if the results are the same. I have another 50 and those shots are were no where near what these look like.

The default task when debugging these issues without dedicated test gear is to switch things around: try the lens in question on another body, and try a similar (i.e. 50mm) lens on this body. It’s useful to know your 35 works fine, but that has greater depth of field so it’s not completely viable as a test. But still.. it does suggest the fault lies in the lens.

The extended red sensitivity of the SFX200 film should not be an issue unless you were using a deep red filter (for dramatic sky) or an IR filter (to capitalize on the IR spectrum). Its normal-light sensitivity should focus in the normal way.

The fact that your lens is ‘mint’ doesn’t mean it’s factory-new. It means only that it’s been well cared for —and was very possibly disassembled for CLA and reassembled without checking its accuracy. Inspection and re-CLA by a competent lens guy seems to be the solution.

 

[ckjr23]

I tried with cinestill bwxx and got that same results. I'm convinced its the lens

Maybe the film in use?

Ilford SFX 200 is a special film, as description from the Ilford site:

"...ILFORD SFX 200 is a medium speed black & white film with extended red sensitivity which makes it the perfect choice for infra-red style images. "

I have and use with pleasure the Canon 1.4/50 with normal film, it's a nice lens.

Enjoy with more "common film" ...

 

[PRJ]

I used to shoot a lot of Infrared and the focus shift can be severe. I just checked my 50 1.4 and it has a huge adjustment for infrared. You need to refocus the lens to the R spot. In other words after you focus, move the spot that is at the infinity mark to the R mark. The blurriness might also be because visible light and infrared light are being focused very differently from each other. You may need to filter one out when using the lens, or stop way down.

Hope that helps you.

 

[ckjr23]

I removed the rear element on the lens to check it out and noticed the washer was incredibly loose around the metal casing. So loose that it seemed like that washer wasn't meant for that lens. I adjusted it and will see if that fixes anything.

 

[Scrambler]

I removed the rear element on the lens to check it out and noticed the washer was incredibly loose around the metal casing. So loose that it seemed like that washer wasn't meant for that lens. I adjusted it and will see if that fixes anything.

I'm a little lost with this.

Rear element?

Washer?

If you can post some photos it might become clearer. Then I can compare with mine and advise.

 

[ckjr23]

I've got three files attached. One is the back of the lens before I took it apart locked at infinity, one is of the gold washer (after I took the lens apart) I mentioned and the last is a top down view of the washer (its not the best photo). The way that it used to sit was really loose almost as if it was sized incorrectly. I compared it to my 50mm 1.8 and although they are different sizes, the washer on the 1.8 fits perfectly. I've seen a few videos that this washer can affect focus so I'm wondering if this is the cause of my issue.

Hopefully this makes sense.

I'm a little lost with this.

Rear element?

Washer?

If you can post some photos it might become clearer. Then I can compare with mine and advise.

 

[jonmanjiro]

The gold colored washer is a shim and is meant to be loose. All it does is position the optical cell with respect to the lens focusing unit. When the optical cell is attached to the focusing unit, the shim is held firmly in place between them. Assuming the shim is the correct thickness now, if the shim is made thinner the optical cell will sit closer to the film plane and you will get back focusing, and if the shim is made thicker the optical cell will sit further in front of the film plane and you will get front focusing.

Your problem may be a loose element in the optical cell. Try shaking the optical cell and listening for a rattle in there. Make sure you hold that shim and have the aperture wide open to prevent rattles from them.

 

[ckjr23]

I'll check it out. I appreciate the information!

The gold colored washer is a shim and is meant to be loose. All it does is position the optical cell with respect to the lens focusing unit. When the optical cell is attached to the focusing unit, the shim is held firmly in place between them. Assuming the shim is the correct thickness now, if the shim is made thinner the optical cell will sit closer to the film plane and you will get back focusing, and if the shim is made thicker the optical cell will sit further in front of the film plane and you will get front focusing.

Your problem may be a loose element in the optical cell. Try shaking the optical cell and listening for a rattle in there. Make sure you hold that shim and have the aperture wide open to prevent rattles from them.

 

[ckjr23]

I just took the lens apart and shook it and I hear rattling in the optical cell.What does that mean?

The gold colored washer is a shim and is meant to be loose. All it does is position the optical cell with respect to the lens focusing unit. When the optical cell is attached to the focusing unit, the shim is held firmly in place between them. Assuming the shim is the correct thickness now, if the shim is made thinner the optical cell will sit closer to the film plane and you will get back focusing, and if the shim is made thicker the optical cell will sit further in front of the film plane and you will get front focusing.

Your problem may be a loose element in the optical cell. Try shaking the optical cell and listening for a rattle in there. Make sure you hold that shim and have the aperture wide open to prevent rattles from them.

 

[Scrambler]

I just took the lens apart and shook it and I hear rattling in the optical cell.What does that mean?

Jonmanjiro is the guru, I won't step in the road.

I believe the short answer is: "a lot more trouble to fix."

But HOW, that will take the expert.

 

[ckjr23]

Hey all,

It seems as though I fixed my issue. I went out and shot a test roll and most of my shots are 1000x better than what I was getting before. Not 100% sure what I did other than adjust and made sure everything was tightened properly.