Focusing difficulties with M645

[olivioargenti]

I have a Mamiya 645 SUPER with 35, 80, 150 and 210 lenses which I have used for

portraits and full body photos often taken in fairly low lights (I use 400 ISO,

tripoid). I have difficulties with correctly focusing. I believe this was due

mainly to the fact that I was shooting at f/4 or f/5.6. I also find it

difficult sometimes to clearly adjust the focus as the round FOCUSING circle

gets black and does not allow me to see properly. When this happens, focusing

the eyes gets sometime impossible, so I settle to focus on the mouth or the

nose, hoping that with f/8 or f/11 I will get the eyes OK too (I have just

recently done some tests but will geet the results in September due to summer

vacation).

 

 

Anyone can kindly advise me on this particular issue?

 

 

I have difficulties in reading but see well in distance although I also suffer

from some astigmatism. When I use my reading glasses for shooting, I see

everything blurred and must take my glasses out. I also have prescription

glasses, not to be used for reading, with astigmatism correction. When I use

them shooting in low light I only see a marginal improvement on the clarity of

the overall picture. Should I need a diopter?

 

 

Thank you

 

 

Olivio

[jean-louis llech]

It is a real problem, and many people who wear corrective glasses have it. I permanently make an up/down movement, (front/nose) with my glasses, as I cannot focus through them.<p>

 

On your Mamiya Super, you probably have the standard focusing screen with microprism and RF spot. You can change it for a matte one, without microprisms or RF split image. I use one on 6x6 cameras and I have less focusing problems.<p>

 

Then, before buying corrective diopter lenses, try the 2.5x magnifier which is available for the Mamiya Super, and which can be mounted on the prism. The magnifier is easy to mount or remove on the eye-cup, and a 2.5 magnification helps focusing.<p>

 

Do you use the waist level viewing hood or a prism ? <br>

You can find some diopter correction lenses either for the prism or the WL finder, if you have a "classic" correction.<br>

The AE prism finder has a frame for mounting diopter correction lenses. Six correction lenses, from -3 to +3 are available.<br>

You can also buy a corrective lens tailored at your sight by an optician. But you will nevertheless need a Mamiya frame to mount it on the prism eye-cup.<br>

For the waist level viewing hood, Mamiya has also six diopter correction lenses from +2 to -3. (+2, +1, 0, -1.5, -2, -3)<p>

 

But before using standard correction diopter lenses (which will probably never fit exactly to your sight), try to focus with the matte focusing screen and the 2.5x magnifier.

[john_bright]

Olivio

 

This is a complicated issue, so perhaps I should just explain how I approached the problem with my Bronicas some years ago. First of all my ordinary eyesight is quite good but I require +2.5 diopter glasses for reading comfortably. To make things more complicated the standard eyepiece on Bronicas (and I believe most cameras) is -1.5 diopters, not "0" so anything you add has to be added to -1.5. Another problem is that the focussing point of a camera eyepiece is different to that of reading glasses, so the 'correction diopter' doesn't have to be quite as strong as one's reading glasses. In my case +2.0 diopters was adequate. So I added +2.0 to -1.5 and came up with +0.5. I then fitted +0.5 diopter correction lenses to both WLF and Prism Finders and focussing became as clear as a bell. Your case is different from mine but this info should give you somewhere to get started. By the way! Once you can see sharp focussing with your standard lens, all the others should be fine to.

[steve_levine]

I would make sure my focusing screen is correctly seated. This can cause all sorts of trouble.

[charles.]

Are your lenses set to the M mode? When you say the focusing circle gets darker it sounds to me like the lens is stopped down while you are focusing. Try switching it to A and see if that helps.

[olivioargenti]

Many thanks to all of you. I will follow your advice which I am sure will bring improvement. Regards

 

Olivio