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View Full Version : Do I need a recessed lensboard?



Clement
29-Nov-2003, 08:54
New to LF. Purchased a Toyo-View 4X5 and a 150mm Schneider APO-Symmar lens. With the front and rear standards as close together (and aligned parallel) as possible (minimum bellows draw), I cannot focus at infinity with this lens.

Do I need a recessed lensboard?

If I need a recessed lensboard, which one do I need?

Thanks.

N Dhananjay
29-Nov-2003, 09:04
That sounds odd - a 150mm on a 4x5 should not need a recessed lensboard. If this is a 4x5 camera, the bellows extension when front and rear standards are drawn as close together as possible is typically about 75-90mm, so as you increase this distance the lens will bring things into focus. I'm presuming you were trying to focus at infinty or some distance away and you started by setting the front and rear standard about 6 inches apart. If not, try that and rack the focus back and forward checking on the ground glass if the focus improves. Cheers, DJ

David A. Goldfarb
29-Nov-2003, 09:24
You should certainly be able to focus a 150mm lens without a recessed lensboard on a 4x5" camera with a normal bellows. I think DJ is right to think that you've just gone past infinity.

Ted Harris
29-Nov-2003, 09:24
You need to rack yoru bellows out to around 150 mm to focus a 150 mmlens at infinity. With th ebellows fully compressed you will never focus the lens. The amount of bellows extension you need to focus a lens at infinity is akways about the focal length of the lens (wiothout going into the math). For closer focus you will need MORE bellows extension.





Welcome to the wild and wonderful world of Large Format

Clement
29-Nov-2003, 09:35
Go figure. I just bought this Toyo 4X5 camera. As it turns out, the front standard was reversed; thus, it was impossible to focus at infinity at any point between minimum and maximum bellows draw.

I flipped the front standard around and was able to focus at infinity without any problem.

Thanks for your comments!