Diopters in medium format

ParkerSmithPhoto · Jun 21, 2018

Since I wear reading glasses, should I be using a diopter in my Hassy waist level finder, or is the flip up magnifier providing what I need? I use a 1.25 lens for reading, should I have the same in the finder?

Reason I ask is my handheld stuff has gotten WAY soft lately. I used to use a Bronica SQ with a split prism and never had any problems. Now I use a Hassy with the standard (non-split) viewfinder and dang I have wasted some film!

shutterfinger · Jun 21, 2018

I use 1.75 reading glasses. I rarely use a TLR with flip up magnifier but when I do I do not use the reading glasses with the magnifier. The distance from my eye to the viewfinder makes a big difference as to how sharp the image appears through the magnifier.
Your Hasselblad should be the same. Waist level means waist level not mid chest or shoulder high.
Don't rule out body error. Tripod mount the camera, measure from the film plane to a diagional subject such as a fence or brick wall at the center of the frame, set the lens distance scale to the measured distance and make an exposure with the lens wide open. Use a subject distance of 6 to 10 feet.

Sgore · Jun 22, 2018

When I first got my 500C I was having trouble getting focus. I have a -2 prescription. I bought a chimney finder for about $50, and used it for months with great satisfaction. It has an adjustable diopter, so I would point the camera at a blank wall, or a white flat, and adjust the focus of the chimney until the lines on the ground glass (focus screen) were dead sharp. Then any problem I had in the field was my fault. It's not pretty, and you can't lock down your adjustment, but it works and works well. I don't use it much anymore, but thats because my problem was related to a very dim screen

Slixtiesix · Jun 22, 2018

I have -0,75 and buying the -1 magnifier for the waist level finder really improved my focusing. I saw the difference immediately when I swapped the magnifiers, the point of focus seemed much more pronounced.

jeffreyg · Jun 22, 2018

I have a 6x6 Schneider magnifying loupe that I use for looking at negatives that came with an attachment that will let you replace the Hasselblad waist level viewer with it. That might be the answer to your problem. I'm not sure they still make them so a search might be necessary. You could use it at eye level. Best to use a tripod to prevent camera movement regardless.

http://www.jeffreyglasser.com/

Stephen Prunier · Jun 22, 2018

I have been wondering the same thing with my RZ67. I think I'll try some test shots with and without my reading glasses while using the magnifier.

Frank53 · Jun 22, 2018

Get the chimney finder or change the diopter in the standard magnifying loupe (they turn up on ebay). I have reading glasses 3. I found a diopter with the same strengt, exchanged the ground glass by the brightest I could find with split image and beside that I have the chimney finder to choose. The only problem is that depending on light conditions I need my glasses to adjust exposure
Regards,
Frank

Truzi · Jun 22, 2018

This is something I will have to deal with someday, so I'm interested.

However, to get a bit off-topic, is the problem specific to WLF/ground glass? Does presbyopia also cause issues with a prism?
With a prism finder isn't one usually looking through the lens, not on an image projected onto glass?

Sirius Glass · Jun 22, 2018

I cannot comment on using the WLF, but with the PME 45° [prism] I can shoot with or without glasses or wear my contact lenses. I find that I am most comfortable photographing with my contact lenses.

abruzzi · Jun 22, 2018

A very similar question came up recently on another forum, and while I’m not very knowledgeable on the topic, the most believable response is that even though the ground glass may only be a few inches from your eye, the standard diopter places the screen optically 1 meter from your eye. So whatever you need to see things 1meter away, you will need to see in your camera. This jives with my experience. I see close up fine, but need glasses for distance vision, looking through the viewfinders on my cameras is fine for me with no glasses but not with my glasses on.

If correct, and you can’t normally focus on objects a meter away you chose would be to use corrective lenses or change the diopter to something different.

macfred · Jun 22, 2018

I'm still looking for a diopter lens for the manifying loupe of my Rolleiflex 3.5F - those are very rare these days.
May be an optomestrist can cut one on the lines of the standart diopter lens? Any experiences here?

abruzzi · Jun 23, 2018

macfred said:
I'm still looking for a diopter lens for the manifying loupe of my Rolleiflex 3.5F - those are very rare these days.
May be an optomestrist can cut one on the lines of the standart diopter lens? Any experiences here?

I don't know the diameter, but maybe something from here might work:

https://www.edmundoptics.com/optics...lenses/VIS-0-Coated-Double-Convex-DCX-Lenses/

macfred · Jun 23, 2018

abruzzi said:
I don't know the diameter, but maybe something from here might work:

https://www.edmundoptics.com/optics...lenses/VIS-0-Coated-Double-Convex-DCX-Lenses/

Thank you, abruzzi! That's a comprehensive range of lenses ...
I will need some personal advice, therefore I'll take the Rollei to an optometrist.

abruzzi · Jun 23, 2018

Yeah, I’m not sure how serious my suggestion was, unless you know what your doing, but if you can’t find originals, that may be the closest you can get.

Ian Grant · Jun 23, 2018

Yes best get the right Diotre, I was lucky about 18 months ago and got two very cheaply for my Rolleiflex E2 off ebay from Japan. They were only cheap because the seller hadn't used the right terminology in English and I spotted what they really were.

I'm abroad so can't check which I have but they do make life and focusing a lot easier, I guess they are also much higher quality optically compared to the fixed flip up magnifiers of my Yashicamat 124, RolleifleX Automat and Microcord.

Ian

shutterfinger · Jun 23, 2018

Reading glasses are designed for best focus at 12 to 14 inches.

macfred · Jun 23, 2018

shutterfinger said:
Reading glasses are designed for best focus at 12 to 14 inches.

So it would be no help to transfer the diopter of the reading glasses to the magnifying loupe.
My reading glasses are +1dpt - what diopter is needed for the magnifyier loupe to use it without glasses ?

shutterfinger · Jun 23, 2018

macfred said:
My reading glasses are +1dpt - what diopter is needed for the magnifyier loupe to use it without glasses ?

I don't know. I move the camera up/down until the grain of the gg is sharp or the grid line(s) of the gg are sharp then hold the camera at this distance for focusing/composition. I try to position the finest detail in the subject center of the magnifier to focus then compose.

Ian Grant · Jun 24, 2018

Truzi said:
This is something I will have to deal with someday, so I'm interested.

However, to get a bit off-topic, is the problem specific to WLF/ground glass? Does presbyopia also cause issues with a prism?
With a prism finder isn't one usually looking through the lens, not on an image projected onto glass?

With a prism finder you're just looking at the ground glass with the image projected on it by the lens and the prism is correcting the inverted image (upside down and back to front). With a fast lens and bright screen you may not realise there's a screen there

I noticed the other day I was struggling slightly to focus a Pentax Spotmatic so need to get an eyepiece dioptre ideally, these seem rare though, it would be useful if the same one fitted my Mamiya 645 cameras. My Canon DSLR has eye-piece adjustment and I do need it and some of my rangefinder camera also have eyepiece adjustment..

With SLRs and TLRs a lot depends on the speed of the lens ( and the screen brightnessViewing in the case of TLRs) an f1.4 lens snaps easiliy in and out of focus and f3.5 lens is more difficult and of course slower Zoom lenses on DSLRs and film cameras can be the worst which is why Autofocus is now the norm.

Ian

shutterfinger · Jun 24, 2018

Anyone want to bring their Hasselblad with waist level over and let me see what I can do with it?
I've got a fresh box of Ektar 100 and a fresh box of Portra 160 in the desk drawer.

alentine · Aug 5, 2018

Still using my eye glasses which is not comfortable, but accurate.
It needs to be resolved for each camera alone.

choiliefan · Aug 5, 2018

I've ditched my SLR WLF's in favor of magnifying hoods equipped with variable diopters.
My eyes and cameras are old and nailing the focus is getting harder every day.
Variable diopters have simplified things immensely.

Sirius Glass · Aug 5, 2018

I found that I see the best using contact lenses when using any of my cameras.

wiltw · Aug 5, 2018

Truzi said:
This is something I will have to deal with someday, so I'm interested.

However, to get a bit off-topic, is the problem specific to WLF/ground glass? Does presbyopia also cause issues with a prism?
With a prism finder isn't one usually looking through the lens, not on an image projected onto glass?

Yes, if you find a need for reading glasses when reading a novel, you likely would find a need for compensating optics in a camera focusing system -- waist level or viewfinder!!!
A viewfinder is typically set by the manufacturer to have an apparent distance of about 30-36" (manufacturer dependent distance), so if you eyes can focus at that distance without assistance, you wouldn;t be in need of diopters for camera. If you need adjustment for 'reading' (at about 14-16" apparent distance) you might still be able to get away with no diopter for the 30-36" distance.
Diopter strength for cameras NOT necessarily expressed in absolute values (as measured by an optician), but are sometimes expressed in 'additional-diopter strength from the factory-suppled standard ndiopter'.

alentine · Aug 5, 2018

Sirius Glass said:
I found that I see the best using contact lenses when using any of my cameras.

Sirius,
In Hasselblad system, What's the the finder that gives the biggest magnification plus diopter around or just more than -3.5 dipoter?
Thanks.

Diopters in medium format

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