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Lars Åke Vinberg
15-Dec-2001, 13:53
I am putting together a 6x9cm kit for landscape/travel photography - finally got my tax return. I have a 4x5 camera, so this kit will complement the 4x5. I see a possibility of adding a scanning back later.

Looking at performance charts only, the new digital series (Digitar, Sironar-Dig ital) from Schneider and Rodenstock look quite attractive. But I have not yet sp oken to anyone with experience from these lenses, and I'm sure there is more to a lens than MTF charts.

Any input on the my lens choice below is appreciated.

Very wide: Sironar-Digital 45/4.5. Very similar to APO-Grandagon 45/4.5, includi ng performance charts.

Wide: Grandagon-N 65/4.5.

Moderately long: Digitar 150/5.6 or Sironar-Digital 150/5.6 or 180/5.6. All thre e have very nice performance charts and cover 150 mm.

With my 4x5 I currently have a Grandagon 90/6.8 and a Nikkor 135/5.6 which I'll might sell.

/?ke

Neal Shields
15-Dec-2001, 17:51
This is more of expanding your question than answering it. It is my understanding that pixels don't like light rays strikeing them at sharp angles. Therefore "digital" lenses are designed so the the light strikes the sensor cell as close to 90 degrees as is practical. That would seem to mean that for a given focal lingth you would have to bend the light more than with a normal lens??? If so I would expect more aberation than with a normal lens. Also I would expect a smaller image circle??

neil poulsen
15-Dec-2001, 17:56
I enjoy shooting 6x7 on my 4x5 camera. One advantage is that the additional space around the negative reduces the potential for internal flare. I dislike losing contrast to flare.

Subtracting for what one loses along the edge of a (not quite) 4x5 negative, I use 1.6 as a multiplying factor (3.625/2.25) to convert focal lengths from 6x7 to 4x5. With this in mind, I like the following selection of lenses for both 6x7 and 4x5.

6x7 4x5

150mm 240mm

120mm 192mm

90mm 144mm (About 150mm)

75mm 120mm

58mm 93mm (About 90mm)

47mm 75mm

36mm? 58mm

Notice how 6x7 lenses convert to commonly used 4x5 lenses also used for 6x7. I don't know if lense manufacturers planned it this way, but it tends to work out. One doesn't have to "recalibrate" to visualize in either format.

As to particular lenses, I use Super Angulons for medium or shorter focal length 6x7 lenses and get good results, although I don't enlarge 6x7 above 8x10. I don't know about digital, but 20 years ago, people (e.g. A.A.) were saying that lenses had enough resolution to exceed the ability of film to record detail. So, it seems like one could use the same set of lenses for both 6x7 and 4x5, especially the current Apo lenses.

Glenn Kroeger
17-Dec-2001, 10:14
While Neal is right about digital sensors having some problems with high incidence angles, they do not change the laws of optics! For a given focal length lens, the geometry of rays is the same for all optics.

The main difference with "digital" lenses is that they are designed with different optimization criteria. Since digital sensors are smaller, they have smaller image circles. In exchange, they achieve better performance at larger apertures. These larger apertures help reduce the high incidence angle effects. Finally, special attention is paid to eliminating chromatic aberations which produce such noticible color fringing on digital sensors.

These same criteria are beneficial for roll-film use, however given other factors such as film MTF and film flatness, the improvements over traditional lenses may be marginal. Additionally, if you continue to use "4x5" tactics of shooting at f/22-f/32, you definitely won't see any advantage since diffraction will rule.

giancatarina
17-Dec-2001, 14:41
the best combo? : 55 apo grandagon (cover 4x5) & grandagon N 75/4.5 & apo sirona r S 135 or 150 (or apo symmar) or 47XL & grandagon N 65 & super symmar 110 XL & apo symmar 180 with all these premium class lens, you can use roll film and 4x5 !!! or keep your lens for now, and buy just the 55 apo grandagon and the sinar zoom 2 roll film holder (4.5x6 to 6x12 !!!)

Dominique Cesari
17-Dec-2001, 14:47
Glenn wrote : "For a given focal length lens, the geometry of rays is the same for all optics" Not at all : think to telephoto and retrofocus design.

Glenn Kroeger
17-Dec-2001, 16:38
Dominque: The geometry of the RAYS IS the same for telephoto vs long non-tlephoto, only the physical position of the optical elements changes.

Dominique Cesari
18-Dec-2001, 14:59
<The geometry of the RAYS IS the same for telephoto vs long non- tlephoto>

At least for the part of the path between the digergent group and the film.

And for retrofocus design ? (which is not a concern for LF, I must admit)

Lars Åke Vinberg
9-Jan-2002, 17:24
Thanks all for your replies. I have decided on Schneiders: 5.6/47 SAXL, 5.6/65 SA 5.6/100 Apo-Symmar, 5.6/180 Apo-symmar.