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Tim_5941
27-Jan-2006, 23:33
I just got back from the lab my first 2 rolls of 120 using a DAYI 6x12 film back. Every image had the same problem.
Each image has a 8mm section that is clearly underexposed compared to the rest of the image. This section is located on the far right of each image. This section that is underexposed has a sharp line, it isn't a fuzzy transistion. Directly next to this sharp line of underexposed film is evidence of some sort of light leak - next to the sharp line in all images it appears the image is overexposed for a few mm, though the transition is back to the rest of the image is smooth, no clear line is visible. Most images are not completely blown out in this area, and in some it's hardly noticable. There are however a couple taken when the sun was higher that have a good 10mm section completely blown out to white and then pink fringing before returning to the image.

I'm a bit perplexed where to start with this as although it seems there is a light leak, I can't see how one small section of the image is also clearly underexposed each time and why there is a firm transition at this section.

I'm still waiting to get my 4x5's transparencys back from the trip, but the last set I took were fine and showed no evidence of this sort of problem (fingers crossed it is the film back causing the problem - I hope all my 4x5's from the trip aren't like this as well!)

Unfortunately I don't have access to a scanner at the moment so I can't show you scanned images, so it may not be possible to identify the fault., but any suggestions would be great

- tim

Tim_5941
28-Jan-2006, 00:13
I tried a quick makeshift solution. I'm not at home, so I don't have my lightbox or my good digitial camera, but I borrowed my girlfriends and held the slides up to the monitor with a white background and photographed them - looks like crap but you can see the problem:

http://www.saxtim.com/sports/P1120001.jpg

this next one shows one of the two that showed major evidence of a light leak:

http://www.saxtim.com/sports/P1120002.jpg

tim

Brian J Nelson
28-Jan-2006, 00:31
It looks to me like a fogging of most of the area except for the edge that you think is underexposed. Do you lock down the back with the graflock mechanism or just use the spring pressure of the ground glass to hold the back firm against when you wind the film. I ask because I have experienced similar fog with the Sinar 6x12 back when I did not lock it down. When I advanced the film, the back pulled away slightly fogging the film.

Michael Gudzinowicz
28-Jan-2006, 06:23
It looks like the dark slide light trap is jammed open or is missing. Take the lens off the camera,
and look into it while holding a bright light near the opening in a dark room.

Patrik Roseen
3-Feb-2006, 08:35
Hi, it looks like the usual linear fogging that also happen on the very similar ShenHao 612. I have commented this in another thread. But here is what I did to solve it.
I have examined the 'light-blocker' where the dark-slide is inserted and found a quite simple device with black cloth on the side facing the slide and some thin metal 'legs' which is functioning like a spring. But this is only on one side of the slide on the other side its only the metal frame itself. When I received my holder the 'legs' where not spread wide enough to block the light and I have therefor increased the tension by spreading them further. I still do not trust it enough to remove the darkslide completely. On the shen hao this is found under a metal plate attached to the holder with 4 small screws.

Asher Kelman
10-Mar-2008, 21:53
So is the Dayi worth getting? How does it compare to Cambo/Calumet 6x12 adapters?

vinny
10-Mar-2008, 22:23
Mark your darkslide with a marker at the point where it's pulled out far enough. Don't pull it out past that.

David Crossley
10-Mar-2008, 22:56
Like Vinny says, mark your darkslide.

<So is the Dayi worth getting?> The Da Yi is very good value. Holds the film flat is light tight and has accurate film spacing.



David Crossley/Crossley Photography....

Asher Kelman
13-Mar-2008, 02:01
David and Vinney,

If you have Quickloads would you leave them behind and choose the 6x12 for cost or convenience or film choice? I'm asking myself how much one would use the 6x12 when one can crop the 4x5. Is it that 6x12 fits better to the panoramic scene and you don't like cropping 4x5 pieces of film and wasting?

Asher

Patrik Roseen
13-Mar-2008, 05:25
David and Vinney,

If you have Quickloads would you leave them behind and choose the 6x12 for cost or convenience or film choice? I'm asking myself how much one would use the 6x12 when one can crop the 4x5. Is it that 6x12 fits better to the panoramic scene and you don't like cropping 4x5 pieces of film and wasting?

Asher

I think it is more a matter of cost for processing. To process a 120film with six 6x12 photographs is equal to the cost for processing one 4x5" sheet if you hand it in to a professional lab.
There is also a more variety of film to choose from in 120 format.

Regarding convenience the 6x12 back makes most sense when using the rangefinder on the LF-camera. If focusing on the groundglass there is a need to remove the groundglass to attach the Rollfilmholder for every new shot (unless bracketing ofcourse).

Now bracketing is another thing in itself since with rollfilm one has to process every photographs the same way, i.e it is not possible to adjust the processing for a second sheet based on the result from another sheet in a series of 'brackets'.