Another cult lens

[Ed Bray]

Thomas and Roland, both of you have inspired me to do this with my 50mm f1.4 PKM, I wonder if either of you would have some of dimensions required or how you would calculate them, such as:

a) the diameter of the tube
b) the diameter of the bore of the tube
c) the total length of the tube
d) the diameter of the step of the tube both inside and out
e) the depth of the step

Would the optimum focusing distance not be circa 3 mtrs (for 'environmental portraits')? infinity should be easily taken care of by using depth of field, if so is there a way of calculating the length the tube would need to be to give this figure?

To adapt my adapter to bring up the 50mm framelines would I need to grind away 1mm from the sloped area to give a depth of circa 2.5mm instead of the 3.5mm it currently is (which brings up the 35/135mm framelines)?

TIA

 

[ferider]

Nice work, Thomas.

Ed, this is the tube I bought:

I didn't have access to a lathe, so I filed it until it fit over the metal ring around the rear element (taking the ring off, and the element out, first). Regarding length, have a look at your other Leica lenses, start so that the RF cam is barely longer than the lens mount. Then take a file or grinder from there. Unfortunately I cann't measure the exact inner cam dimensions anymore, since I don't have a native lens anymore.

Regarding focusing calibration, I wouldn't worry too much. Both lenses that I modified were very close in true focal length to the Leica 51.6mm RF calibration (see my measurements in the first post - that's sheer luck with the Pentax lens, other SLR 50s might be less useful). Much better than, say, the typical Russian lens that you can buy. I calibrated the two Pentax SMC cams to match my M3s at infinity, and they work well on close up. Thomas' lens is a bit too far off at 100cm, but this could be the Bessa too, IMHO (all my Leicas (7 ) are down to a quarter inch focus accuracy at 100cm, and I can measure this with high repeatability. The Bessas I tried were by far not as accurate - distance varies depending on the direction of the focus, etc.)

This is the first lens after infinity calibration, and test shot at 1m on film:

and this the second:

You can see a little variation, but nothing that would matter in a real world portrait situation, IMO, on film at least.

Also, both adapters that I tried (Novoflex and Kipon) brought up 50mm framelines out of the box. If yours brings up 28/90mm framelines you can file it down, if it brings up 35mm framelines you are out of luck.

Roland.

 

[semilog]

I'll try to post some measurements from my lens's focus tube later today (mine is press-fit, not glued on). I ordered exactly the same part from McMaster-Carr that Roland did.

 

[Ed Bray]

Nice work, Thomas.


Also, both adapters that I tried (Novoflex and Kipon) brought up 50mm framelines out of the box. If yours brings up 28/90mm framelines you can file it down, if it brings up 35mm framelines you are out of luck.

Roland.

Thanks Roland, I'm confused now, my adapter brings up the 35mm framelines, but my 50mm adapter has a deeper curve than my 35mm adapter by at least 1mm, or is this not the feature that brings up the framelines? I have checked all three LTM-M adapters I have 35mm, 50mm & 90mm and this is the only thing I can see that changes between them.

I'll try to post some measurements from my lens's focus tube later today (mine is press-fit, not glued on). I ordered exactly the same part from McMaster-Carr that Roland did.

Thank you, that would be appreciated if you could, my next door neighbour is a toolmaker and he can sort me out if he has the relevant measurements.

 

[Jerevan]

I would love to have a lens like this. I still miss the 50/1.4 I had.

If it would have been possible to re-make one of the earlier 55 mm M42 lenses, I'd be in heaven. But re-reading the thread I see that it would not work. So I have to hunt down some other lens instead.

 

[Thomas78]

Thomas and Roland, both of you have inspired me to do this with my 50mm f1.4 PKM, I wonder if either of you would have some of dimensions required or how you would calculate them, such as:

a) the diameter of the tube
b) the diameter of the bore of the tube
c) the total length of the tube
d) the diameter of the step of the tube both inside and out
e) the depth of the step

The dimensions I used:


a) 35 mm
b) 33 mm
c) about 18 - 18.5 mm after trimming down
d) 34.4 mm
e) I did not record this, but a bit more than the step at the ring of the last element of the lens

Would the optimum focusing distance not be circa 3 mtrs (for 'environmental portraits')? infinity should be easily taken care of by using depth of field, if so is there a way of calculating the length the tube would need to be to give this figure?

The problem ist that you can have spot on focus only at one distance if the travel from minimum distance to infinity is not exactly the same between camera and lens.

But I think that my lens might be a bit out of spec since it gives a focus of 94 cm at f/1.4 when the scale shows 100 cm (with my Bessa R3A).
Perhaps I shoud test this again with my Leica M3...

 

[Thomas78]

But I think that my lens might be a bit out of spec since it gives a focus of 94 cm at f/1.4 when the scale shows 100 cm (with my Bessa R3A).
Perhaps I shoud test this again with my Leica M3...

Now I did test my Leica M3 at 1 m distance:

First with my DR Summicron I get the focus at 98 cm for f/2 both when I set the scale to 1 m or use the rangefinder.

With the Pentax M lens I get the focus at 96 cm for f/1.4 and between 96 and 98 cm for f/2.

I also noticed that the resolution of the Pentax-M improves significantly when stopped down to f/2. At f/2 I have the impression that the Summicorn has an advantage in resolution at f/2 against the Pentax-M.

 

[ferider]

Cross-post with my 50mm thread ....

Using my SMC 50/1.4 (on an M4P) last week in Zurich, seeing my two girls Daphne and Raail, on Legacy Pro 400, HC110(B):

Hard to focus a 50/1.4 close up and wide open sometimes .... but not because of the lens !

Roland.

 

[ampguy]

Roland, these are great images of your daughters. It's amazing how you have managed to get this lens to RF couple. Someday, I'd like to try one of these in K-mount on a small sensor digital, to see if some of the magic comes through.

 

[ferider]

Thank you, Ted !

 

[ferider]

Wind-mills

Wind-mills

Trying to see how rectilinear the lens is .... on Leica M4-P, TMY, HC110(B) with a red filter:

 

[semilog]

The SMC-M on the M6 has emerged as one of my favorite camera-lens combinations ever.

These are all shot to TMAX400 (2TMY) developed in XTOL 1+1.

20140413-2014_25_029.jpg by Semilog, on Flickr

20140413-2014_25_018.jpg by Semilog, on Flickr


20140413-2014_23_019.jpg by Semilog, on Flickr


20140413-2014_26_001.jpg by Semilog, on Flickr

 

[semilog]

By the way, Roland, I have not done a careful comparison, but I've noticed no evidence of vignetting wide open at infinity with my lens.

 

[ferider]

By the way, Roland, I have not done a careful comparison, but I've noticed no evidence of vignetting wide open at infinity with my lens.

Good to know. Thanks !

 

[semilog]

Now I did test my Leica M3 at 1 m distance:

First with my DR Summicron I get the focus at 98 cm for f/2 both when I set the scale to 1 m or use the rangefinder.

With the Pentax M lens I get the focus at 96 cm for f/1.4 and between 96 and 98 cm for f/2.

I also noticed that the resolution of the Pentax-M improves significantly when stopped down to f/2. At f/2 I have the impression that the Summicorn has an advantage in resolution at f/2 against the Pentax-M.

My results with the SMC-M are similar. I calibrated to infinity with the RF of my M6. Wide open at 1-2 meters the lens front-focuses by perhaps 2.5 to 3 cm versus the RF. At f/2 contrast improves markedly and the front focus is about the same or just a bit less.

 

[NickTrop]

--- or, you can just bite the bullet any buy a Spotmatic for $30... (Kidding. That's why this is RFF, of course...) PS Nice work/great photos. I have this lens (which lives up to its billing) on a K-mount Vivitar V3000 (Cosina-made). I made it K-mount (after letting it enjoy a few weeks out in the sun to reduce the yellowing) by filing a little notch in the lens for the bayonet locking pin and screwing in an M42 adapter really tight (no apoxy required, and I can take it off it I want to) after removing the spring and some metal "thing-y" from the adapter. Did the same for an M42 Jupiter 9 (also lives up to its billing). Works a charm. -- And THAT is the outer limit of my capability to perform outpatient surgery on camera lenses. Hats off t' ya, sir.

 

[semilog]

Absolutely true, Nick. Although I am no more a fan of the Spotmatic than I am of my old Nikkormat. Both are cameras that I love in principle but not in practice. An MX or LX, on the other hand…

 

[NickTrop]

Some nice person, semilog, just last week heard I like "old cameras" and anonomously left a Pentax ZX-5 (with a craptastic Tamron zoom I will surely never use...) on my desk at work to have. Ordered the batteries online, awaiting arrival and now hunting for a proper Pentax-A prime for her to take advantage of all the automated "A" features (except autofocus -- who needs it?). I only have one "A" Pentax - a 19mm/3.8 Vivitar (nice budget ultrawide but that's a specialty lens). Either going to go cheap with the Pentax-a 50mm f2 or pay a tad more for the 1.7. I like the f2. It looks almost like a pancake lens. It won't be seeing the "A" version of the 1.4 -- a tad too $$$, plus I already have the "M" version, which will see some action on the new body.

 

[charjohncarter]

I have an ZX-5, prone to failure on a couple of fronts, but mine is still working. And like you I like the in-focus bing of thru the finder light that tells me 'in focus.' The beauty of the ZX-5 is that you ring control the aperture and dial control the shutter, or go auto. I have the 20mm FA, the 28mm F, and the 50mm f1.7 F. I have a few others but what you get is aperture control that you can see and not look around at a screen (and pushing buttons). You get shutter control with the camera dial and see over-under in the box viewfinder. I used mine today with the 50mm f1.7 and autofocus, which like you I don't use much, and it worked fine. I looked around at AF boxes and I like this one the best, but they do fail.

You will not be unhappy with the f1.7, but if a good buy on a f2.0 comes get it; it is probably better for most general use.

If I were younger I would buy a few ZX-5 bodies and send them the Eric H. for plastic parts upgrades so I would always have a working body.

 

[NickTrop]

charjohncarter -- thanks for the heads up on the electronics failure. I might just hold off on getting any lenses for it now until I get the batteries in the mail and can test her out and see if it works. I was actually a little -- I dunno -- not wanting it, as odd as that sounds. I am trying to limit my camera collection to some carefully selected users. And I have a sentimental attachment to my "K-mart special" all manual Vivitar from the late-80's, a gift from my dad that was the primary camera used as my kids grew up. Learned photography with that all manual plastic fantastic cheapie and it still looks/works as new. I hate to retire her as one of my users (as irrational as this is...). However, when I read the manual for the ZX-5 online, I became intrigued especially at how nicely it implements aperture priority mode. I became enthused at the possiblity of shooting aperture-priority with my Super Tak 1.4 or Jupiter 9 for portraits. The more I read the manual, the more I liked the camera. I hope it works. Thanks for sharing your experience with this camera. I'm really looking forward to shooting it. Nice pic, by the way.