15mm lens - coupled or not?

[thegman]

In the end I've gone for the LTM version, it's less expensive with the finder, M adaptor and shipping than just the M lens, so I've ordered one from a shop in Hong Kong. I may try that filter trick depending on how happy I am with the filterless results.

 

[gliderbee]

There's a guy named Ben who comes on here sometimes who devised this method...you just pop the glass out of an inexpensive 39mm filter, grind off the male side, and sand it down until you can wedge it in there...you can firm it up with a bit of epoxy or silicon glue. He used a brass B&W filter, but mine is a cheap aluminum Tiffen or something...

I'm interested in this, but the picture is not showing; can I see it somewhere else ?

[EDIT]: Forget my question: I can see the pictures now ...

Thanks,
Stefan.

 

[sahe69]

IMHO, the advantage of the m mount version is the ability to mount filters.

Second that.

 

[Juan Valdenebro]

Garry,

When I got my 15 I did a test I shared here but I don't have it now (one year ago).

It's not true that if at f/4.5 you set focus at 6 feet you will get infinity on focus.

I really wanted to have that under control so I printed the shots from Tri-X with my enlarger: at f/4.5 and the focus at 6 feet, infinity is a bit out of focus. It improves by f/5.6, and then it improves again by f/8... And it even needs f/11 to get the best on infinity.

You can test it yourself...

Cheers,

Juan

 

[Roger Hicks]

Dear Juan,

Indeed, d-o-f is grossly overrated. But even rough guesses (not as rough as '6 feet for everything') are covered by d-o-f in most cases.

Cheers,

R.

 

[binky]

It's not true that if at f/4.5 you set focus at 6 feet you will get infinity on focus.

I really wanted to have that under control so I printed the shots from Tri-X with my enlarger: at f/4.5 and the focus at 6 feet, infinity is a bit out of focus. It improves by f/5.6, and then it improves again by f/8... And it even needs f/11 to get the best on infinity.

I heard mentioned that this might have something due to circle of confusion(??) that it's best to use good judgment (as with anything) in scale focusing.

Can some elaborate?

thanks in advance

 

[Roger Hicks]

The bigger you blow the picture up, or the closer the distance at which you examine it, or the better your eyesight, the less the d-o-f.

Some d-o-f tables are predicated upon postcard-size enlargements at arm's length, examined by average 60-year-olds without glasses...

(I have average 60-year-old eyesight, or perhaps a fraction better, but it was a lot better at 50.)

Cheers,

R

 

[jan normandale]

..

Some d-o-f tables are predicated upon postcard-size enlargements at arm's length....

I've never thought about how DoF charts are/were derived. That's actually pretty interesting.

 

[ampguy]

some great resources on DOF history

some great resources on DOF history

and calculations:

http://dpanswers.com/content/tech_crop.php#dof

http://www.zeiss.com/C12567A8003B58B9/Contents-Frame/71E8DD8F96A9CF14C125697700546F2F

Interesting on how Zeiss feels DOF has changed over time, therefore the CoC k-constant evolved from ~1000 to ~1500

Does this mean our older lenses DOF scales are too generous? Probably.

I've never thought about how DoF charts are/were derived. That's actually pretty interesting.

 

[jan normandale]

Interesting on how Zeiss feels DOF has changed over time, therefore the CoC k-constant evolved from ~1000 to ~1500

Does this mean our older lenses DOF scales are too generous? Probably.

thanks , this is interesting from a tech PoV. I'm familiar with DoF and using it but this clarified the idea behind the 'markings' for DoF on many lenses. More reading ahead...

 

[Krosya]

Seriously?

Seriously?

Dear Garry,

Quite honestly, anyone who can't guess the distance accurately enough for a scale-focus 15mm probably shouldn't be taking pictures.

Cheers,

R.

Really? I used to have a Heliar LTM version and I came across the situation that images just plain didnt have that "snap" that point of focus brings. I'm seriously considering M version as I sold the LTM one just because of that. Actually, there is a really good thread about it here:
http://www.l-camera-forum.com/leica-forum/leica-m8-forum/84780-new-super-wide-heliar-15mm-m-2.html

 

[Roger Hicks]

Really? I used to have a Heliar LTM version and I came across the situation that images just plain didnt have that "snap" that point of focus brings. I'm seriously considering M version as I sold the LTM one just because of that. Actually, there is a really good thread about it here:
http://www.l-camera-forum.com/leica-forum/leica-m8-forum/84780-new-super-wide-heliar-15mm-m-2.html

My own suspicion is that there was something wrong with the lens in this case, possibly register: remember that depth of focus is inversely proportional to depth of field. At what distances/apertures were you shooting? Did you try focusing via a tape-measure or external rangefinder? Because if the lens is correctly focused, it doesn't really matter whether it was focused by RF, yardstick, ground glass, or guesswork.

I am surprised that some people find it hard to guess well enough for a 15mm, given that many were happy enough with guess-focusing 105mm lenses on 6x9cm, but evidently there are those who can't do it, or think they can't. If they're happier with coupling, fine, but equally, Zeiss took the same view I do with the 15/2.8, over a stop faster than the Heliar: there was just no point in coupling.

Cheers,

R.

 

[thegman]

I've put a few rolls through the 15mm now, and indeed, I've had no trouble focusing at all. Usually, I've just put it on infinity and pointed in the right direction and got the photo I wanted. It's a lovely lens, very sharp and gives a FOV which makes the most mundane scene look interesting.

 

[awilder]

The size smaller size and closer focus are more of an advantage, especially since I plan to use it on a Panasonic G1, effectively giving me a 30 mm lens that focuses down to 0.3 meters vs 0.5 meters.

 

[Krosya]

My own suspicion is that there was something wrong with the lens in this case, possibly register: remember that depth of focus is inversely proportional to depth of field. At what distances/apertures were you shooting? Did you try focusing via a tape-measure or external rangefinder? Because if the lens is correctly focused, it doesn't really matter whether it was focused by RF, yardstick, ground glass, or guesswork.

I am surprised that some people find it hard to guess well enough for a 15mm, given that many were happy enough with guess-focusing 105mm lenses on 6x9cm, but evidently there are those who can't do it, or think they can't. If they're happier with coupling, fine, but equally, Zeiss took the same view I do with the 15/2.8, over a stop faster than the Heliar: there was just no point in coupling.

Cheers,

R.

Well, I'm not sure, but I think my lens was fine. Some photos came out very well, yet some (these are mostly one that had focus of interest closer, not just infinity) just didnt have it. It's like even with a 35mm lens - if miss focus even by just a a little - it's not the same. Photo can look focused, yet no "snap". Sometimes I would get lucky with it and get it right - just as I liked it, but I finally got sick of chancing it. Plus 15mm lens is a challenge in itself, so missed focus just didnt help things for me. Or maybe I'm just more particular. So, one of these days I'll try a new M version and see if I like it better. I have a feeling that I will - after all - there are seem to be many other people that had similar issues with LTM version of 15mm Heliar.

 

[Krosya]

Well, I did get the M-Heliar 15mm and I tell ya - its one great lens. It feels very good - sturdy and well built - better than ltm version. Not to say ltm one was a poor quality - it's just that M-Heliar is seems to be better and smoother. And I do like the ability to focus the lens. It may not seem like much to some, but I feel more surefooted now. And it handles nice as well it handles flare well. Here are a couple shots from RD1s - I have not had a chance to use it as a true 15mm yet. So it is a well handling lens on RD1 as well.:

 

[Finder]

A couple of comments, the DoF scales would not be accurate for an RD1 as the sensor size is smaller than 35mm. You lose about one stop--if the aperture is set to f/8, use the f/5.6 scales.

Secondly, depth of focus is proportional to the f-number. DoF nor focal length has any effect on depth of focus.

 

[Cron]

some days ago I got the Millich adapter/shade for the old CV15 to mount an uv/ir-filter into it for use with a Leica M8;
first shots are satisfying;
no problems with focus at distances beyond 2m

 

[JohnTF]

The bigger you blow the picture up, or the closer the distance at which you examine it, or the better your eyesight, the less the d-o-f.

Some d-o-f tables are predicated upon postcard-size enlargements at arm's length, examined by average 60-year-olds without glasses...

(I have average 60-year-old eyesight, or perhaps a fraction better, but it was a lot better at 50.)

Cheers,

R

Just hope the arm length is not averaged from members of the NBA?

Regards, John