Lens roller-coaster - Canon f1.2

[pfogle]

Well, after secretly lusting after one of these lenses for more than a year, I finally bought one in great condition - paid far too much for it!

Cleaned out a bit of haze from the inside surface of the rear lens group (easy - takes 10 mins, apparently needs doing about once a year or so) and filed down (*gasp - horror* 😉 ) the tab that acts as the infinity lock - which is a pain otherwise.

It seemed to have a front focus problem - and I was contemplating sending it off for collimating, which would have cost around 50-80 pounds. Out of curiosity, I unscrewed it from the adapter to see if it was feasible to open up the back and do the shims myself. When I screwed it back into the adapter, the front focus problem had mysteriously disappeared! No idea why - maybe the focus cam roller hadn't been seating quite properly. Now I'm scared to take it off the camera in case it goes out again 😱 🙂

The file names on the attachments show the aperture of each shot.

The 100% crop is a bit over-sharpened and suffers from being over-compressed, but it shows what the lens can do in the center.

 

[pfogle]

I sold the 50/1.5 Nokton to get this lens, and I had a lot of doubts about that, as the Nokton is such a sharp lens, but in the end, it's not really sharpness that I'm interested in - and I never used it seriously in all the time I had it. Don't really know why, I just didn't bond with it. I sure hope I get on with this one!

 

[Terao]

I have one of these as well. Haven't used it nearly enough yet - bought primarily for my Canon P - but I love the creaminess to backgrounds, and the way its built. It also does a pretty good job of noctiluxing out of focus specular highlights 🙂

I'm thinking its going to be a fun portrait lens...

 

[rover]

The 1.2 is the hot lens these days. I sold mine around the holidays, but honestly I miss it.

I enjoy the way people describe it too when they get one. The overall comment is that they like it, as I did, but it is a different beast. Very unique image character from it. Not like any other 50mm lens I have used.

 

[Terao]

I also paid far too much for mine but it was in such good condition (bar a little oil on the blades) that I just had to have it. Basically unused and I felt it was worth it for the price of a Nokton f/1.5
I'll be taking it to Portugal (off on holiday in a couple of weeks) and using it as a street/interior lens I think...

 

[Joerg]

hi,

i just got one over the Holidays and love it.
My preferred low light/portrait (OK target is my toddler...). At 1.2 it is a little soft for my taste but it improves very much at 1.4. Also very good at smaller apertures


Ciao

Joerg

 

[pfogle]

Update - I did a whole lot of adjusting the RF and trying various lenses with a ruler, and I got them all pretty much focusing correctly except the 40mm Rokkor and the Canon 1.2. The others front focus around 1-2 cm, but I reckon that's the camera, and to get any better adjustment I'd have to take the top off, which I don't want to do at this time.

The lenses that work are the wides and the two summicrons - which I reckon will probably be good, so they're the de facto benchmark.

Anyway, I decided to bite the bullet, and fix the remaining two lenses by grinding down the spacer rings. Both lenses turned out to be very easy to get into, and I took off a small amount of brass of each of the spacers using fine grit emery paper on a mirror to get a flat surface. It took a while, but worked out fine.

Upshot is; the Canon is a lot sharper wide open than I thought it was 😀

nuff said.

 

[tmessenger]

One thing you have to watch for is the adapter thickness on screw mounts. I got a M adapter with a lens I bought and it was .043" thick (not .039 1mm) so this was the problem.

Tim

 

[jlw]

Recently I learned something else that may be a factor in the observation that many people seem to find this lens front-focuses a bit on M-mount cameras.

I've got a reprint of the factory Canon 7s service manual, and one of the specs quoted in it is for "focal plane." This is quoted to be 28.94mm +/- 0.02mm, as measured by a dial gauge at the four corners.

This article (link) on Dante Stella's website, discussing focus variations between Leica M and Konica Hexar RF bodies, gives several different measurements for Leica and Konica bodies, none of which correspond exactly to the value Canon used. (In comparing Dante's measurements, remember that the M body depth is 1mm thinner than the screwmount body depth.)

These differences constitute the various manufacturers' different assumptions about how thick the film is and how much it will curl up in the film channel, which allows some clearance in excess of the film thickness to avoid scratching.

I think Canon must have assumed a bit more film bulge than Leica did, causing them to position their lens slightly farther outward. So, the lens would focus correctly on a Canon body... but when mounted on a camera set up to Leica's assumptions, the lens would be a bit too far from the film plane, causing it to focus in front of the rangefinder-indicated position.

This is just a theory, since I don't own a Leica for comparison measurements, but it seems plausible. As has been noted above, it doesn't take much shift to make a visible difference in the plane of best focus, given a 50/1.2 lens's slender DOF at close distances.

 

[ferider]

Good stuff, Phil. Black magician ...

Like said above, the adapter can play a role. I recommend a Leitz adapter,
or if you have an adapter that works, leave it on the lens forever ...

While I think the Canon and Leitz standards match (I have several
fast Canon lenses that are exactly right on my M bodies, with film tests
- and these bodies work too with Nikkor and Leitz lenses ...),
I believe the Canon 50/1.2 suffered sample variation, i.e.
not enough quality control ... But then you can observe similar
sample variations with modern lenses, like CV lenses, for instance.
These don't show in normal situations, since shooting a tape
measure at close distance is an extreme test.

Best,

Roland.

 

[pfogle]

Another update - this is from an email I just sent to RichC...

Those screws are barmy! After I went through the whole process last night with the Canon, I discovered that in adjusting screw 1 and 3 I'd accidentally moved the infinity point, which I couldn't check from my room until this morning.


Good news: both the summicrons seem to be working fine.
Bad news: I chopped off about 0.15mm too much from the shim in the Canon. Fixed it this morning by cutting a paper circle and putting it under the spacer. Seems OK - will test more.

Meanwhile, I can't get rid of that stubborn 1-2 cm front focus that I now attribute to the RF so I'll have to
a) live with it
b) tackle screw 4
c) send it in to someone - (who?)

The only place I know that adjusts RFs is Sendean in Soho, but I don't think they've ever done the R-D1. Robert White will only look at new ones. So I guess, unless it drives me crazy, it's going to be option a 🙂

Anyway, the only lens I intend to use wide open is the Canon, so I don't mind tweaking the lens to fit the RF if that's what it takes.

ps - the tab summicron ('85 model) is amazing! I had no idea what I've been missing 😀

so now I've got 3 portrait lenses - the tab for the rugged guys, the collapsible for the ladies and the Canon for the wrinkleys 😉

pps - If your camera or lenses need adjustment - keep them as far away from me as possible!

Phil aka the hacker 😀

 

[ferider]

Phil, the lens hacker, 🙂

live with 1-2cm front focus - as long as you know when you shoot it's no problem.
One inch is within the RF accuracy for any RF camera (even an M CLA'ed by Don or Sherry).
Your body back-lash will be more in most cases. Here is my wide open 50/1.2,
on an M3, CLA'ed by Sherry:

(tape is in inches).

Don't forget the nail polish on the RF screws, they tend to drift otherwise.

I hate to say it: now is the time to go out and use the system 🙂

Cheers.

Roland.

PS: a friend taken with the above system:

 

[pfogle]

You said it Roland!

The photo of Janet, my wife, holding the glass in the second post above, is why I'm persevering with this lens - when I look at that shot it's like falling in love all over again (we met in '72 😀)

ps, re the lacquer, can you do that safely without removing the topplate in your opinion?

ps not missing the Nokton one bit 😉

 

[ferider]

I have only done it on the Bessa R3a, Phil. I used a tooth pick and just a little
nail polish through the flash shoe. Be careful, if you put in too much and it runs
off the screws you risk gumming up the RF.

I know what you mean wrt our wives 🙂

Best,

Roland.

 

[RichC]

ps, re the lacquer, can you do that safely without removing the topplate in your opinion?

Very awkward to reach with the top plate on, and screw 1 is almost impossible to seal.

 

[pfogle]

One thing that's interesting is that, if you read the posts, esp. on pnet about this lens, people often say it's hard to focus, and/or soft.

What I've noticed is that, when you finally get it set up right, it actually focuses quite reliably, and is surprisingly sharp in the centre, even wide open. I reckon most of the posters have probably had small residual errors that they hadn't diagnosed. It's only through a lot of trial and error that I've got a setup that I have some confidence in, and I was pretty taken aback when it popped into focus, and I could see what I'd been missing.

I'll shoot some stuff outside tomorrow, weather permitting, and post them then.

 

[ferider]

One thing that's interesting is that, if you read the posts, esp. on pnet about this lens, people often say it's hard to focus, and/or soft.

What I've noticed is that, when you finally get it set up right, it actually focuses quite reliably, and is surprisingly sharp in the centre, even wide open. I reckon most of the posters have probably had small residual errors that they hadn't diagnosed. It's only through a lot of trial and error that I've got a setup that I have some confidence in, and I was pretty taken aback when it popped into focus, and I could see what I'd been missing.

I'll shoot some stuff outside tomorrow, weather permitting, and post them then.

Fully agree, Phil. I always thought the "soft" statements came from

1) flare/glow behavior wide open (which I really like)
2) just to many badly adjusted lenses out there. For some reason Canon quality control was not great with this lens.

Best,

Roland.