question on Focusing on SLR

[raytoei@gmail.com]

I find my focus out of whack, and I would appreciate your comments.

Using my Leicaflex SL and Summicron 50mm, I find that that sharpest point is usually about 5 - 10cm (EDITED) behind my subject, this results in a blur to slightly unsharp image, I tried this with the 50mm lens, the 135mm lens. I have eliminated hand shake as I try to shoot at least 1/60s.

Here are my questions:

a. I wear contact lens or glasses. If my contact or glasses are not accurate, will that affect my ability to focus properly ?

b. My habit is to zoom in until it is blur, then zoom out until it is blur and then zoom in again back and forth. Is there a better method (besides Auto Focus which isn't an option here).

c. Lastly, with Range Finders, if the picture isn't sharp, one of the reasons could be due to a misaligned rangefinder. With SLR, this is eliminated because what-you-see-is-what-you-get, is this largely correct with respect to focusing ?

thanks people.

raytoei

 

[kshapero]

You probably need to have that rig looked by a expert repair person.

 

[Keith]

I used to think that what you see is what you get with an SLR but that's not necessarily true. Incorrect distances for mirror and focusing screen would play havoc I'd imagine.

I agree that the camera probably needs attention!


Have you taken any pics with the camera on a tripod and with the lens set at f16 and infinity. Unless there's a film plane problem that should give a sharp image!

 

[raytoei@gmail.com]

Hi, just a follow-up:

I tested the Chrome SL and my Black SL today. I placed several objects in different distances and I ran a roll on each SL. I run the test through each eye twice.....

The Chrome SL is the culprit. The objects being focused turned out unfocused while the back objects were sharp. On the Black SL, everything was sharp and objects being focused turned out sharp.

(if anyone has instructions on how to fix this, pls point me the way. Thanks!)

thanks again.

raytoei

 

[Ronald M]

Where the screen is positioned relative to the mirror and film is what counts. I know one person who was doing lots of quality black and white and he bought numerous SL`s and a large portion showed focus problems with his 280 2.8.

What you see is not what you get. If the mirror stops in the wrong place, you see to high or too low. If the screen is positioned to high or too low, you get back or front focus.


I just put a Katz Eye screen in my Nikon digitals 200 and 700. The manual focus screen was out on both. Nikon conviently has an adjustment screw that raises or lowers the screen height. The auto focus system is different and located in the base of the camera and the two do not necessarily coordinate.

I think the leica screen is set with shims if it is not machined in properly. It is a very critical adjustment that will be measured in a few 1/10000 of an inch.

 

[sig]

I have once opened a Minolta SRT. The mirror box can be adjusted up and down with screws in the corners (compared to the screen), maybe something similar on your leica...

 

[antiquark]

I read somewhere (but never tried it) that you can test the focus of an SLR by putting a spare groundglass where the film should be, then inspecting the image with a loupe. If the viewfinder is in focus, but the groundglass isn't, then there's a problem with the mirror or viewfinder calibration.

 

[ferider]

You have a mis-aligned screen. With used SLRs a frequent, but on the internet rarely reported problem.

 

[payasam]

It could be the screen, as Roland says, or it could be the mirror.

"What you see is not what you get," Ronald M said. It's through the lens all right, but light travels to the film and the eyepiece along two different paths.