This question is specific to one lens. Nikon says the 720 tele nikkor will over 5x7 and some have thought maybe 8x10 even though the specs say no. Anyone have one and tried it on 8x10 to see? I know the 600/800/1200 covers 8x10. I am wondering if the odd note I read awhile back by someone who 'thought' the 720 would has any facts behind it.

-- Dan Smith (shooter@brigham.net), February 22, 2002

Answers

Dan,

The 720mm Nikkor-T I have not used but I have frequently used the 360mm and 500mm configurations and the specs for all focal lengths are about the same as i recall. I can tell you there is not a lot of movement on 4x5 so I feel their claim even for 5x7 might be optimistic ... and that would be on axis.

Walter Glover

-- Walter Glover (walterg@netaus.net.au), February 23, 2002.

Hi Dan

In the Nikon brochure is the diameter at f 22 stated with 210mm(5x7) and at f 16 154mm The rest is up to you!

-- Armin Seeholzer (armin.seeholzer@smile.ch), February 23, 2002.

Dan,

I have a Nikkor-T with the 360mm, 500mm and 720mm rear elements. I use all of the elements on my 4 x 5 Wisner Technical Field and have never had a problem. It is a suberb lens.

I had never tried it on 8 x 10 because I had heard that it wouldn't work. Your question prompted me to find out for myself and the results surprised me.

I just mounted the Nikkor-T on my 8 x 10 Deardorff and focused all three elements on inifinity.

The 360mm element doesn't come close, though it would probably cover 5 x 7 just fine with limited movements.

The 500mm element almost makes it a f/64. I can get two corners to show on the groundglass, but not all four.

With some careful adjustments, the 720mm element appears to work at f/64! And would probably very slightly vignette at f/45. I have not shot film to prove it, but I can see the full aperture at all four corners of the groundglass. So, it should work. Mind you, this is at infinity with absolutely no movement possible.

I certainly would not have bought this lens to shoot 8 x 10, but it's nice to know that, if the circumstances were right, I could do so. Thanks for inspiring me to discover this.

-- Don Harbor (letdondoit@mindspring.com), February 23, 2002.

Interesting observations - that the 720mm seems to cover 8x10 at very small apertures. But, that being so, just what sharpness level can one expect from this lens at f45/64? Some previous posters on the optical quality of this lens have indicated mediocre sharpness at best.

-- John Burnley (oreamnos1@fnol.net), February 24, 2002.

I would be cautious about concluding that a lens will cover 8x10 based on a ground glass image. An image that looks fine on the ground glass can appear quite soft when the film is examined. It also depends on how much enlargement you plan--the coverage of a lens for a negative plenty good enough for a contact print can be larger than the size of the image of sufficient quality for an enlargement.

-- Michael Briggs (MichaelBriggs@earthlink.net), February 27, 2002.

Hi Dan-

I recently bought a Calumet C1 and tried out several of my lenses with it including a 720 Nikkor T using Provia II. It covered 8x10 easily @ f45 and was sharp corner to corner. It looked good on the ground glass at f16 while I was focusing.

jim

-- Jim Bancroft (bancroft@cox.net), May 30, 2002.