Soft Film/E24 Backs/Shooting Wide Open?

[mark_tucker2]

I shoot a Hasselblad 202FA with E24 backs. Recently, I have

noticed a considerable amount of film coming back from the lab,

noticeably out of focus. I am trying to pin down the source.

 

To make it worse, I tend to always shoot wide open, which I'm

sure tests the ground glass and film backs tolerances.

 

These are my thoughts on what could be happening:

 

#1: Maybe when the assistant is loading the film, he's getting in

a hurry and maybe the film is not being kept under that little silver

metal tab. Could that affect the focus or film flatness? (Best to

always start with an avenue that blames the assistant, rather

than me)...

 

#2: Maybe it's related to shooting 220 instead of 120? Could

there be some film thickness issue that makes the tolerances

worse for 220?

 

#3. Could the ground glass be knocked loose somehow, so as

to affect the focus on the glass? (Doubt this, because it's not

every frame).

 

#4. Could the 220 film be curling up somehow inside the back?

 

#5. I'm 43, and have had eye tests, but maybe as a last resort,

it's my eyes. But I am SUPER PARANOID about this issue, so I

rarely ever release the shutter if the ground glass image does

not pop sharp.

 

#6. Maybe it's the 45 degree finder that's on the body. could that

affect focus tolerance?

 

If anyone's had this happen, and solved it, I'd sure like to know.

Or even to narrow down the range of possibilities.

 

Thanks, Mark Tucker

 

http://marktucker.com/

[henry_a]

Didn't anyone tell you you'd go blind? ; > )

 

As I understand it the 220 backs are better for film flatness than 120. You might want to do a test for focus or send it off to be checked by Hasselblad. Shoot some film at some small targets placed on a yard stick pointed diagonally away form the camera. If the ones you focus on are sharp the camera is OK. If not you can see on the yard stick where it really is focusing.

[gene crumpler]

First check the ground glass focus against the scale on the lens. If these agree, I'd suggest you get a split image screen and a slight diopter correction eyepiece. I found it hard to get accurate focus on the plain/microprism screen. I have a -3 diopter eyepiece on the prism and my Rx is -2.50. This gives a bit of overcorrection, but brings the split image into very sharp focus.

 

If not then the screen needs to be shimmed to get the scale, groundglass and film image to agree.

[gene crumpler]

If the scale and the film image don't agree, a trip to the shop is in order.

[john_hicks___]

>#1: Maybe when the assistant is loading the film, he's getting in a hurry and maybe the film is not being kept under that little silver metal tab. Could that affect the focus or film flatness?

 

It probably could but I don't know that it would.

 

> #2: Maybe it's related to shooting 220 instead of 120? Could there be some film thickness issue that makes the tolerances worse for 220?

 

220 should actually be a little better since there isn't the paper backing to contend with.

 

> #3. Could the ground glass be knocked loose somehow, so as to affect the focus on the glass? (Doubt this, because it's not every frame).

 

I think the mirror could be out of position but this also would probably show up in every frame.

 

> #4. Could the 220 film be curling up somehow inside the back?

 

Yes, rollfilm does essentially that. Shooting wide open can make it obvious.

 

> #5. I'm 43, and have had eye tests, but maybe as a last resort, it's my eyes. But I am SUPER PARANOID about this issue, so I rarely ever release the shutter if the ground glass image does not pop sharp.

 

But it still may be your eyes. Borrow a chimney finder (which has an adjustable eyepiece) from someone and shoot with it a little and see if it solves the problem or makes focusing easier. To properly adjust the eyepiece, look through it at the screen with no lens on the camera and adjust the eyepiece until screen markings or focus aids are as sharp as you can get them. If you have a screen with no aids or marks just use the readily-visible dust specks. The leave the eyepiece at that setting while you use the camera.

 

> #6. Maybe it's the 45 degree finder that's on the body. could that affect focus tolerance?

 

Yes, and this goes along with your eyes. The prism doesn't give a whole lot of magnification plus you may need an eyepiece diopter.

[marios pittas]

> #6. Maybe it's the 45 degree finder that's on the body. could

> that affect focus tolerance?

 

Once my finder was not properly attached to the camera body (not a Hassy - I may add :-) ) driving me crazy with focusing (since I was shooting at f/32 or so there was no problem with the prints). Something worthwhile to check.

 

HOWEVER, I was taught by a pro long ago that the best way to check any medium format equipment (and large format I guess) is to use the Polaroid back!!!! Least fuss, least cost. Lot a pack, put on the tripod and test to your heart's desire!

 

That should reduce the problem to possibilities: 1, 2, 4.

 

p.s. Nice great web site, inspirational!

 

p.s.s On the funny side: If you face senario no 5, maybe it is time to re-consider purchasing the H1? :-)

[squareframe]

Mark,

 

it seems you should assess your 120 results with an E12 back first, to eliminate the optical-path unknowns. and of course, film goes under the tab. less coffee perhaps?