My 8x10 only has 400mm max bellows and when I tried focusing a Fuji C 450mm f12.5 mounted on a 32mm top hat it just misses infinity. I am wondering if I will get an on focus image if I stopped down the lens. I understand DOF works if I calculate a focus point between the far the near distances where I want to be in the zone of focus. But what if I can't achieve infinity focus at all?
It's not going to work. Either get a tophat board or a new camera.
The flange focal length for this lens is 425.3mm, so you should be able to obtain infinity with the 32mm extension. Perhaps you're doing something wrong (measuring, for a start).
As for DoF, you should be able to produce a clear (though possibly not sharp) image if you stop down far ebough, regardless of whether you can achieve infinity focus (based on the measurements you provided and the FFL for the lens).
Lachlan.
You miss 100% of the shots you never take. -- Wayne Gretzky
The camera is an Ebony SLW810 and I racked it out and still no infinity focus. The top hat is a 35mm extension my mistake. I bought the lens knowing the specs and thought it should work. I tried doubling up the extension to 70mm and the lens does focus so there is nothing wrong with it. I know I am not going to use it if I need to attach it to a really long top hat. Maybe I'll get another 8x10 some day! Thanks for the replies!
If you do have 400mm extension and you are using a 35mm TH, it should focus PLUS give you about 10mm extra. How much extension do you have with the 79mm TH in place?
Lachlan.
You miss 100% of the shots you never take. -- Wayne Gretzky
I didn't physically measure the bellow length. I just took it for granted the manufacturer's specs are correct. I will measure it later today.
Well I am peeved to say the least! I just measured the bellows fully racked and it is only 14.5 inches or 370mm well short of the official 400mm spec.
Sometimes you can get more extension by using base tilt and axis tilt together.
Jon
my black and white photos of the Mendocino Coast: jonshiu.zenfolio.com
My camera does not have those movements. It only has front rise/fall, tilt.Originally Posted by Jon Shiu
Can you do something like this with the front standards to get a bit more extension?
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