Ebony wide angle fresnel with 300mm tele

[Leigh Perry]

I want to use a 300mm tele (probably Fuji 300T) with my Ebony SW45. It has the Ebony wide angle fresnel permanently fitted.

For anyone who has used a 300mm lens with the WA fresnel, is the groundglass image usable? Or am I going to have to buy a second focusing frame / groundglass without fresnel?

Thanks.

[Jim Bancroft]

Hi Leigh-

I've used the 45SW and WA fresnel with a 210mm Sironar mounted on an "top hat" lens board w/o any trouble.

jim

[mark blackman]

Leigh, I use the wide-angled fresnel with a 90mm lens. It's quite easy to slip it on when needed and then remove it. The cost of a sperate back would make your eyes water! Don't forget, the WA fresnel is designed to go on top of the existing one

[George Hart]

Leigh, I don't know how you are going to get a lens as long as the 300 mm Fuji on your SW45! In theory it would be possible with a back extender (not cheap), but with a flange focal distance of 252 mm, stability could be a problem.

I have the WA fresnel on my 45S. This camera allows me to use a 300 mm lens on a top hat panel, and the image on the gg is significantly inferior with the WA fresnel installed compared with the gg screen alone. It is dimmer, and you have to move your head around more, but it is nevertheless easily useable. However I do have a problem with the Fuji 240A lens in dim light eg indoors, when used with the WA fresnel, because the gg image is really too dim to allow me to frame properly. Hope this helps.

[Leigh Perry]

Thanks for the feedback. My experiences have been similar with the Apo Sironar 150S. It is still very usable with the WA fresnel, but not as bright or uniform as without the fresnel.

With a 'top hat' extension lensboard, the Fujinon 300T (telephoto) can apparently be used on the SW45 with plenty of room for movement and closer focusing.

[Leigh Perry]

George, following up your comments on flange focal length of the lens, my reading of the Fujinon page suggests that the 300T is only 195mm, which tallies with other info I have been given about suitability for the SW45.

I believe that 252mm refers to the 400T.

[George Hart]

Leigh, yes the FFL for the 300T is only 195 mm. My mistake (too early in the morning to select the correct figure!) But the max bellows for the SW45 is 190 mm, so in order to get this lens focused at infinity you will need either a back extender (expensive) or a top-hat panel (tilt becomes more difficult with a tele lens design). But I'm sure that there are plenty people who have done it. Alternatively you could consider the Nikkor-T 270, FFD 187.6 mm, which should work at infinity on a flat panel and without a back extender.

[Leigh Perry]

George, thank for the update. Matt at Robert White suggested using the 35mm 'top hat' with the Fujinon 300T. I'll definitely look into the Nikkor.

You mentioned "tilt becomes more difficult with a tele lens design". Is this because of reduce image circle, or is there another factor at work?

[George Hart]

Leigh, a drawback to the Nikkor-T is the smaller image circle, which is listed as 160 mm. However these stated figures are often conservative, and it may be worth asking someone who's got one to give you their experience with useable image circle.

I have no personal experience with tele lenses in large format, but others report that tilt etc. cause apparently greater movements of the image with tele lenses, so that eg after applying tilt you may have to shift and re-focus more than normal. This would be accentuated with a top-hat panel. It's something to do with the fact that the nodal point (?correct term!) of a tele lens is shifted along the optical axis because of the lens design.