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To modify a 40 summicron


Bmorena

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I just got a a 40 summicron with a cl and am so happy with it on my m8 I'm considering making it my primary lens. I find that the 35 frame lines when I preview them is a perfect match so it seems a modification makes sense. Since the 40 lines are always visible in the cl I can't really come up with a good reason not to modify. Any reasons I'm not thinking about?

Thanks

Brian

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.....the only down side is that you will not have the correct framelines in your CL.......

 

That is not correct....

 

Brian,

 

I believe most replies missed what you wanted to know: will the modification of the lens to bring up the 35mm frame on the M8 affect its usability on the CL? The answer is ‘no, it will not’.

 

On all M cameras (except the M3), the 35mm frame is the ‘default’ - in other words, the frame line mechanism does not move when a 35mm lens is mounted. On the CL, the 40mm is the default but the 40mm lens frame actuating lug is the same as the one of a 50mm lens. Hence - when you mount the 40mm Summicron (or Rokkor-M) on an M Leica, 50mm frame lines will be displayed.

 

By modifying the mount of the 40mm Summicron to activate the 35mm frame on the M8, its functionality on the CL will stay unaffected - it will still display the 40mm frame. The modification involves removing a small portion of the frame actuating lug on the bayonet mount.

 

Go ahead and do it - I did it on mine many years ago!

 

Best,

 

Jan

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Maybe you do not have to modify the lens. Recently I found a way to 'lock' the frame choice lever of my M8 in the desired position. This gives me the 35mm frame any time I want it. So my 40cron is untouched.

 

I do not have the time now to post some images of the solution. Give me a few hours and I will.

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Maybe you do not have to modify the lens. Recently I found a way to 'lock' the frame choice lever of my M8 in the desired position. This gives me the 35mm frame any time I want it. So my 40cron is untouched.

 

I do not have the time now to post some images of the solution. Give me a few hours and I will.

 

The only way to 'lock' the 35mm frame lines when using a lens of a different focal length is not to rotate the lens fully to its locked position. This is not a good idea, as the lens is thus not secured in the mount. It is OK to do this with a lens that has to be 'over-rotated' past the locked spot as in order to remove the lens you again have to go past the locked position.

 

You can of course mount the lens normally and than pull the frame lever to bring up the 35mm frame lines but, this may not be always convenient. Modifying the 40mm Summicron is still the best and least 'painful' way.

 

Best,

 

Jan

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Thanks for all the responses. I was aware the cl framelines would be unaffected but I've read that some prefer to retain the 50 lines with the 40. I'm curious why anyone would prefer the 50 to the 35 lines as 35 seems like such a better match. I suppose a camera with the frame lines set to a deeper distance as well as subject distance would have some effect but I wouldn't expect it to be that great.

Thanks again

B

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Maybe you do not have to modify the lens. Recently I found a way to 'lock' the frame choice lever of my M8 in the desired position. This gives me the 35mm frame any time I want it. So my 40cron is untouched.

 

I do not have the time now to post some images of the solution. Give me a few hours and I will.

 

Please do, I have the same lens and do not want to file it up.

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...I've read that some prefer to retain the 50 lines with the 40. I'm curious why anyone would prefer the 50 to the 35 lines as 35 seems like such a better match....

So am i as the 35mm framelines are a better match at long to short subject distance as well. At least on my Epsons. Is it the same with the M9?

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Thanks for all the responses. I was aware the cl framelines would be unaffected but I've read that some prefer to retain the 50 lines with the 40. I'm curious why anyone would prefer the 50 to the 35 lines as 35 seems like such a better match. I suppose a camera with the frame lines set to a deeper distance as well as subject distance would have some effect but I wouldn't expect it to be that great.

Thanks again

B

 

Brian,

 

The M8 frame lines, as you probably know, are set to show the field of view at 1 m distance. This means that at greater distances the finder shows more than what will be in the image (unless you got the finder upgrade). So - the 50mm frame lines may be a better match for the 40mm Summicron on the M8 with original frame lines.

 

Before you do any filing on the lens mount, shoot off a few images using the 35mm frame and the 50mm frame. Shoot at distances that you do at most times (for me that would be 3m to 6m) and compare which frames are more accurate for your style of shooting.

 

On film M's using the 35mm frame lines for the 40mm Summicron is a no-brainer, on the M8 I would recommend doing some tests as described above and making your decision based on the results.

 

Best,

 

Jan

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Yes - but then you have to run the corrections for a 50 mm lens - and that will not eliminate the rather strong vignetting on this lens.

 

Jaap,

 

Does the 40mm Summicron suffer from "rather strong vignetting" even with the M8's crop factor? That is rather surprising.....

 

Best,

 

Jan

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Jaap,

 

Does the 40mm Summicron suffer from "rather strong vignetting" even with the M8's crop factor? That is rather surprising.....

 

Best,

 

Jan

Well, mine does - obviously the M8 is less affected than the M9, but still... The Summilux pre-asph coding solves the problem, though.
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Hi guys,

 

Here is the solution that 'does not exist' according to some :D

I used a cap of a film roll box. Cut a smal pie-shaped piece of it and then stuck it under the frame lever.

 

Make sure your 'frame-locker' fits with just the right amount of pressure to keep it in place and not too much so that you do not bend the lever.

 

Have been using this solution on my M2 and M8 for a few weeks now and it seems to work fine.

 

The first image shows the 'frame-locker' in place under the lever with the 40cron mounted.

The second shows it on the viewfinder of my M8 to give you an idea of size.

Welcome, dear visitor! As registered member you'd see an image here…

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Well, mine does - obviously the M8 is less affected than the M9, but still... The Summilux pre-asph coding solves the problem, though.

Jaap, did you try to code the 40/2 like a pre-asph 35/2 IV on the M9? If so, did you get more vignetting than with the 35? Just curious given the close fingerprint of those lenses.

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Hmmm IMHO it's not really an option to jam the lever like that:eek:

 

I do not know. It works for me and it acts just the same as when you do it manually.

The major difference is that you do it over a longer period of time.

Will it cause a defect if you keep it that way for weeks?

 

Upwards pressure on the lever is kept to a minimum by choosing the right thickness. I do not see any harm in that.

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I do not know. It works for me and it acts just the same as when you do it manually.

The major difference is that you do it over a longer period of time.

Will it cause a defect if you keep it that way for weeks?

 

Upwards pressure on the lever is kept to a minimum by choosing the right thickness. I do not see any harm in that.

 

It may work for you but, is really not a very elegant solution. Do you carry spare pieces of film boxes with you just in case the one on the camera falls off? What does one do when changing lenses......?:confused:

 

Reminds me of a 'cure' by a backyard automobile 'mechanic' who, when his wife complained that her engine was making strange noises, advised her to turn the volume of her radio up.....:rolleyes::p:D

 

Best,

 

Jan

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It may work for you but, is really not a very elegant solution. Do you carry spare pieces of film boxes with you just in case the one on the camera falls off?

 

Jan,

 

 

When you change lenses you choose to either move the lock to the desired position, or you remove the lock. I agree that you can easily loose it when not in place. I use my wallet for that. Concerning the looks, IMHO you would need hawk eyes to notice the lock when it is in place.

 

 

Spare pieces are not necessary IMO. In case of a loss you can always fall back on the normal way this lens works and move the lever by hand.

 

 

Any way, I feel more comfortable with this than carry two crippled 40crons (I have two ). I always hesitate to apply irreversible/destructive solutions.

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