Graflex.org

[DAB]

I'm the new owner of a SSG. So new, in fact, that I haven't even used it yet. I'm afraid to until a get the owner's manual, which I've ordered. I'm not a photo-newbie, but I am a LF-newbie.

Anyway, my question is this. I have a "chimney" CDS metering finder for my Mamiya RB67. You attach it to the camera in place of the waist level finder, and it enlarges and meters the 6x7 image on the focusing glass. So a light bulb lit up in my brain as I imagined using that finder as a loupe/meter for the SSG. I would have to make some sort of soft mask (felt?) for the 4x5 SSG back so that extraneous light won't mess up the reading.

Not really understanding how to do the calculations necessary when you use a hand held meter and then adjust for bellows extension, I thought this would be a good idea. Can someone tell me if this sounds like a good idea, or why it wouldn't work?

Thanks. The other idea I had was to fashion some way to use my RB67 120 film backs on the SSG. I was thinking of getting the RB67 body part that holds the film back and attaching it to ...something, maybe a Riteway? I don't really understand yet how the graflok back works, so I don't know yet. I am a decent woodworker, so I hate spending 100's of dollars on some adapter when I can make something without too much trouble. More satisfying, too.

DAB

[Dan Fromm]

[Les]

If you've got access to a table saw and a dado head then you should be able to make a frame that about 1/8" thick with the outside dimentions of the 4x5 and the interior dimentions of an RB back.

So now you've got a rail and stile frame. To that you'll add a couple of long triangular wood blocks. top and bottom. These will carry the slide locks that you'll either scavange from a dead RB or you might get them from Calumet. I'd use Poplar, but maple would be a good choice.

The trick will be making sure the face of the film holder lies in the same plane as what would be the mating face of the back of the camera. Otherwise the film plane won't be in line with the ground glass and you'll yell at me. It may take a couple more sticks glued to the opposite side of the rail and style frame to make sure the film holder seats properly.

[45PSS]

DAB, Using a hand held meter for large format is simple; assuming you're using an averaging type meter, apply the readout directly for any lens focused from infinity to close diastace of 6 to 10 feet. Extension factors do not come into play until macro. Spot metering is a little more difficult, one must take several readings and determine an exposure from them.
The Graflok on the SSP works just like the slide locks on the RB. Being the chimney meter was designed to work on the focus screen image of the RB I'd suggest just removing the pop up viewing hood from the SSP and making an adapter to fit the chimney there. It will only give you a reading for the center part of the image as it is smaller than 4 X 5.
Charles

_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.

[DAB]

Three responses already! We are not alone!

Some comments on the comments –

I went home and did a quick and dirty check of the meter. First of all, it already has settings to account for aperture, since it has to do that for the Mamiya. I have an f4.5 Rodenstock 135 on my camera, so I set the meter to 4.5, and set it to the back, and without checking calibration or getting too specific yet, it looks good! I wasn’t planning on mounting it, although that’s an interesting “hands free” idea. I was more thinking of making a soft base, about 5x5, so that I can move it around the focus screen and check focus and meter different parts of the picture.

Regarding the woodworking blueprint, your set up is interesting and is helping me form a mental picture, but I would be worried using 1/8” thick wood – even maple. Just sticking it in, carrying it around, and taking it out of your photo bag could damage it. A stiff plastic or plate metal would work better, I think. Plastic would be easier to cut and glue. I definitely need to spend more time with the camera to figure this one out, and you’re right, especially how to get the proper thickness to make sure the proper focus point hits the film.

45PSS – I see you’re into macro and close-up also. That’s the reason I got the metering finder for the Mamiya in the first place. It’s too difficult to meter macro without it sometimes. But I don’t understand when you say, “Extension factors do not come into play until macro.” Isn’t bellows extension a smooth continuum (from short and bright to long and dark)? Are you saying that I can use my handheld meter and use that reading no matter what the bellows extension (unless it’s very long)? Can you see what I’m confused about? Can you help clear it up? Metering and movements are the two LF peculiarities that I don’t get yet, but learning and enjoying the journey is half the fun!

Thanks for your insights!

DAB

[45PSS]

DAB,
A true 135mm lens will focus infinity at 135mm from the film plane. The same 135mm will focus to 6 feet at say 145mm, I haven't actually measured it. At infinity NO bellows extension would compensation will be required. Technically at 6 feet focus a compensation of +.007 stop would be needed. The same 135 focused 168mm from the film plane would require +1/4 stop, at 202mm from film plane +1/2 stop and so on until focus at 270 (life size) requires +1 stop. You should realize that exposures varrances of less than 1/3 stop can be ignored and very hard to see in the finished product. ( The RB is a horse of a different color with reguard to bellows extension.)
Distance from lens board to film plane in mm, if equal to lens focal length, direct meter reading; for each increase equal to lens focal length add +1 stop esposure; extension more than lens focal length but less than 2 focal lengths add + equivelent fraction.
This is the starting point as each lens/ shutter combination is slightly different, one lens marked f8 might be f8.125 while another may be f7.85.
Does this help settle the debris out of the mix?

Charles


_________________
While a picture may be worth a thousand words, a quality photograph is worth a million.

[ This Message was edited by: 45PSS on 2003-01-30 00:09 ]

[DAB]

Thank you, Charles. Well said. I got it.

BTW (and this is off the above topic - I don't know whether I'm supposed to start a new one or not), I use my Nikon 5T and 6T filters with my Mamiya - they are 62mm high quality close up lenses. I have adapters to get them down to 52mm. How would I get them on to the Rodenstock?

[45PSS]

Somehwhere futher down in this section or in the Lens Help is a thread or two on using filters on the 1000 shutter.
Charles

_________________
The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.