16x20 lens

[Mike Cockerham]

Will someone please give me some info on this lens 16x20 Zeiss Anastigmat Bausch & Lome , such as focal length, and coverage. Will it cover 20x24 for portaits.

Mike

[Ernest Purdum]

We need to know the "Series" number. B&L made several very different lenses under license from Zeiss.

[Jim Galli]

According to my 1913 B&L catalog it's a Tessar IIb f6.3 of 23 1/8" 588mm focal length. Will cover 20X24 at infinity at smaller f stops so you would have movements on a portrait.

[Ernest Purdum]

I took a look to see what B&L Zeiss lenses covering 16X20 I could find. Here they are:

Series VII, No. 10. This is an f12.5, 33 7/8" lens. It is a single cell, composed of four elements all cemented. Two oif them form a Series VIIa f6.320 1/4" lens covering 11X14.

Series IV, No. 8. This also works at f12.5, but is very different, It is a 23 13/16" wide angle.It is aymmetrical with two elements in each cell. Ther were two larger sizes. It would cover 20X24 at small stops.

The Series V didn't have a lens rated at exactly 16X20, but the NO. 9 would cover at small stops and the No. 10 was rated at 20X25.

The Seies VIII Apochromatic Tessar was made in much larger sizes, but I don't think you would want to use one for general photography.

Regarding your question on use for portraits, in general you need to use a longer lens (or a smaller format) for portraits than you would for scenic work. This doesn't have to do with coverage but with perspective. Using a lens inappropriately short results in the huge nose problem. Results you don't want to show to your girlfriend.

[Ernest Purdum]

Jim,

Oops, I overlooked the most likely of the lot. I'm glad you're backing me up.