Originally Posted by
r.e.
The idea of using a lens of about 120mm on 8x10 doesn't appeal to me either. I'd use one as a 4x5 lens.
In post #1, I said that I may also want to use the 4x10 format. Unsurprisingly, Kerry Thalmann says in a 2004 thread called Which Lenses Would You Have for 4x10 and Why? that a 110mm/120mm lens has the same look in 4x10 as in 8x10. Looking at threads on 4x10, it appears that even owners of those focal lengths use them for 4x10 very sparingly, if at all.
For me, what this comes down to is that I don't regard coverage of 8x10 or 4x10 as a consideration when it comes to choosing a lens in the 110mm to 120mm range, including the following lenses on my shortlist chart in post #1:
110mm Schneider Super-Symmar XL f5.6
115mm Rodenstock Grandagon-N f6.8
120mm Schneider Super-Symmar HM f5.6
120mm Nikon Nikkor SW f8
There are a lot of posts on the forum that point out that three of those lenses cover, or sort of cover, 8x10. Some, with different taste than than me, may see it differently, but my reaction is So what? It just isn't a reason for me to choose one of those lenses over another. I'm more interested in price, maximum aperture, range of movement for 4x5, filter size, centre filter requirement and, although secondary for me, weight.
Thalmann was responding to another post. See the second last paragraph:
As everybody knows 4x10 needs at least 273.56 mm.
The actual image diagonal is a little bit less. It will vary slightly depending on which holders you're using, but should be somewhere in the 266 - 267mm range.
I have my eye for Nikkor 120 SW lens. It is 105 Deg, filter size 77mm, circle coverage 310 mm - little movement possible. No center filter needed. Price is very acceptable.
The 120mm Nikkor SW is a great lens and offers the most coverage of the modern wide angles in this focal length range. But, why don't you think a center filter will be necessary? I think the Nikkor SW series are some of the truly great wide angles ever made, but they have to obey the same laws of physics as lenses from Schneider, Rodenstock and Fuji. The fall-off will be comparable to other brands of similar focal length and design. For most standard (non wide angle) large format lenses, illumination closely follows the theoretical ideal cos^4 function. Most modern wide angles (Nikkor SW, Grandagon-N, Super Angulon, Fujinon SW) use a tilting entrance pupil design that results in less iluumination fall-off. In this case, the fall-off of these lenses closely follows the cos^3 function. I've seen illumnation curves for Schneider and Rodenstock lenses, and the illumination does indeed come fairly close to the theoretical ideals (cos^4 for standard designs and cos^3 for tilting entrance designs). I haven't seen any illumination curves for Nikon or Fujinon lenses, but based on my experience with the 90mm f8 Nikkor SW and the 75mm f4.5 Nikkor SW, I'd say they have not been granted an excemption from following the same laws of physics as everybody else.
I'm not saying you will definitely NEED a center filter with the Nikkor SW. It will depend on several variables (your own personal sensitivity to fall-off, your materials and printing methods, etc.). However, you are no less likely to need a center filter with the 120mm f8 Nikkor SW than comparable lenses from Schneider, Fujinon or Rodenstock. Of course, the Nikkor does have other advantages (coverage, size/weight, cost) over most of the competitors.
You also seem to be confusing the terms angle of view and angle of coverage. 120m will be very wide on 4x10. In fact, it's a focal length I like a lot on 6x12cm and 6x17cm (but then, I'm not a huge ultra wide angle user). On 4x5, something in the 150mm - 165mm range is usually considered "normal". Since you're familiar with the 35mm format... a 150mm lens on 4x10 will have the same angle of view in the vertical direction as a 37mm lens in the 35mm format and the same angle of view in the horizontal direction as a 21mm lens on 35mm. So, you can see even the "normal", for 4x5, 150mm lens becomes quite wide on 4x10. For a 120mm lens, the 35mm equivalents become 30mm vertical and 17mm horizontal - extremely wide.
You also mention you need fast lenses for your work. I'm curous why this is a requirement? Do you plan to shoot handheld? Do you want minimal depth of field? Is it a focusing issue? Also, keep in mind that lens coverage specs are usually given at infinity. If you're shooting substantially closer than infinity, the coverage will be larger, possibly significantly, than the published specs.
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