mamiya 645 super calibration ?????

[joe_thomas3]

Hello everyone !!!

 

my problem is this....

 

I have a mamiya 645 super, and i have always been paranoid about the sharpness of images.

I bought the camera second hand on ebay, and never bin 100% about the results I have obtained.

 

I am new to medium format, but used an rz before and have always got fantastic images, sharpness ect.

But this camera, doesnt seem to be dilivering the goods.

 

Short depth of field is great !!!

but anything over f8 seems to be very pixalated/blurred.

Almost 35mil standard.

 

I thinking it might be a lens problem ???

im not sure.

I scan the images in at 600dpi up and over. (on an epson 4990)

 

Could this be a lens problem im having ?

does lens calibration help ?

if so what does this mean ?

 

I really hope people can help !!!

im loosing sleep over this one !!!! ahhhhhhhh

 

and i dont want to sell the camera, as i love the size 645.

 

HELP PEOPLE !!!

 

Best Wishes

 

Joseph XX

[jos__henrique_moreira]

Hi, Joseph.

Is the scanner holding the film in place? Have you scanned the negatives/positives in a film scanner like Nikon Coolscan

9000?

[randall ellis]

Try to rule out one thing at a time. First, look at the negatives closely with a loupe. If they appear sharp to your eye with a loupe, yet they scan soft, then you know if has something to do with the scanning process. If they look soft in the loupe, try a different lens at the same scene. Expose one frame with one lens, then set the other up the same way and expose the scene with that one. Examine both of these with the loupe and see if they differ. If they do you know which lens is the problem, if not, then the problem may be with the camera. Try a different insert to see if the film is being held flat.

 

What shutter speed are you using? Are you using a tripod? Blurred images sound like camera shake or subject movement with too slow of a shutter speed, especially since you mentioned that they are fine up to f/8.

 

- Randy

[joe_thomas3]

thank you all for your comments.

I have bin taking the pictures with a tripod and never anything under a 60th.

But i will try comparing the result of different lenses.

 

But Can anyone explain the process of lens calibration ?

what it means and what it does ?

 

Thank you

 

your comments and advise are much appreciated

 

so thank you again

 

Joseph

[nathancraver]

Just to get the obvious out of the way, and it may sound dumb, but I'll ask anyway. You wouldn't happen to be shooting

120 film in a 220 back, or a 220 film in a 120 back? That would cause focus issues since 220 film does not have paper

backing and a 220 back film plane is closer to the lens than the film plane on a 120 back. I know that on the 645 AFD, you

use the same back and rotate the insert, but I'm not sure if the 645 Super uses separate backs. Have you tried using a

different back in case the one you were using was damaged or had a loose film plane?

[dan_price]

SAME PROBLEM!!

I too have 645 Super and have come up with similar disappointing soft focus results - and i KNOW the camera can perform way better. (Mamiya make great lenses etc).

 

Im pretty sure that with me there is no problem with the lens (I've shot with two different lenses, same same soft problem). Having done some research. i think i know what the problem is.

 

I think it's to do with the mirror calibration and/or focus screen adjustment. If either are incorrectly aligned/positioned/calibrated, the image will not be correctly focused on the film plane (but in the view finder it will look in focus.)

 

The mirror can be adjusted via a tiny (repeat TINY) screw accessable with the lens off. I believe the idea is you set the lens to infinity and view a subject you are certain is at infinity. Then the mirror is adjusted until the subject is properly focused. For the focus screen it is to with up/down height. if this is even the slightest bit out, then obviously you will be incorrectly focusing to correspond with the film plane. This is adjusted again with tiny screws or different sized spacers. Need to check.

 

This week i intend to try and get to the bottom of the problem & fix it!! (HOPEfully fix it at home - no £100 repair fee. Hmm... we'lll see!)

[dan_price]

other helpful/similar threads:

 

http://www.photo.net/medium-format-photography-forum/00F3zL

 

http://www.photo.net/medium-format-photography-forum/00MzLL

 

http://www.photo.net/medium-format-photography-forum/00OL1E

[dan_price]

So i'm now pretty sure of the problem (at least with my camera...)

It's the mirror-stop just inside the camera body. This is what adjusts the height of the mirror via turning THE tiniest screw in the world. It's also made of plastic and is very delicate. I found that mine was bent and when trying to adjust it, it broke. WHOOPS. Going to get a quote from a Mamiya repair place to replace broken part...

 

Not greatest news but now i know for sure why i wasn't getting sharp pics!