Cannot be a Fast Wide Prime -- Nuts!

[wparsonsgisnet]

Advertisement (gone after registration)

See, I look at lenses and see the long ones at f4 and the 50's, and 35's at f1.4 and think, OK, if they're shorter, then they can be wider, so gimme a fast one, too.

 

Well, last night I worked with Robert Eather, who is building a digital camera to photograph the Northern Lights from the Space Station. If you Google this guy, you'll see that he is indeed a very big deal.

 

He is trying to find fast lenses that don't vignette, and we measured my 35-a, 50-a, and 75 'lux's.

 

It turns out that as they get wider, they also vignette more. We were discussing this and he said that the manufacturers could certainly build the lenses so they didn't vignette and that the width of the lens would be the square of the opening, the weight would be the cube, and the cost would be an even higher factor.

 

So, c'mon Leica, gimme the (fastest) wide prime you are able to make.

 

I'll be posting the measurements of my lenses from this work, but the 75 'lux turned out to be very interesting: it has a vignetting factor of only 3 (about 1 1/2 stops) and a transmission factor of .93. Before seeing this lens, Eather had not measured any fast lens that transmitted 90% of the light.

 

There will be a second session and I'll report on the data when this is all done. What a terrific eveing it was!

 

 

Appendix:

 

Dr. Robert Eather is a leading authority on auroral and magnetosphere physics, about which he has written over 65 publications in scientific journals. His book "Majestic Lights - the Aurora in Science, History and the Arts," was published in 1980 by AGU. He produced the films "Spirits of the Polar Night - the Aurora" in 1973, "Earthspace - the Magnetosphere" in 1976, and he provided footage of the aurora for the Imax® film "the Discoverers" (1993). Dr. Eather has received many awards at international film festivals in the science documentary category.

 

His photographs of the aurora have been published in many publications including The New York Times, National Geographic and Readers Digest, and his material has been broadcast on CBS and NBC Television.

 

Dr. Eather has been President of Keo Consultants, Massachusetts, since 1974. He has B.Sc., Ph.D., and D.Sc. degrees from the University of South Wales, Australia. His experience includes working as a physicist with the Antarctic Division of the Department of External Affairs Australia; Auroral Physicist, Australian National Antarctic Research Expedition, Mawson; Research Associate, Department of Space Science, Rice University, Texas; Visiting Professor, Physics Department Boston Collage, MA; Visiting Scientist, Lockheed Palo Alto Research Laboratories; Associate Professor, Physics Department, Boston College, MA; and Research Professor, Physics Department Boston College, MA.

 

For his research work in Antarctica, Dr. Eather was awarded the Polar Medal by Queen Elizabeth II; the Antarctic Medal by the U.S. Air Force; the Antarctica Medal by the National Science Foundation; the NASA Group Achievement Award, Dynamics Explorer Science Team. He received the Convocation Medal for Professional Excellence from the University of Newcastle, Australia; and the Rolex Award for Enterprise. Mount Eather in Antarctica is named in his honor.

 

Regards to all,

[rosuna]

The Noctilux might vignette too much.

 

I would like to see those results!

[marknorton]

Bill that must have been an interesting evening and his thoughts mirror what Leica have been saying, that faster wide-angles present problems. We're lucky to have the 35mm Summilux and 28mm Summicron but there are one or two fast prime SLR lenses out there - the Nikon 28mm f1.4 and isn't there an Olympus as well?

 

If we can't have faster wide-angles, that puts greater emphasis on the next Leica M being full-frame.

[wparsonsgisnet]

Mark, I revisited last nite for a remeasurement of the 50 'lux-a. Eather is sending me the data and I will post his measurements of my lenses. For the most part these three specimens measure better than the published specs. How nice Leica is conservative rather than blowing smoke at us.

 

There IS a 15mm f2.8 R-lens. How 'bout Leica makes an M version of this lens?

[gogopix]

Mark, I revisited last nite for a remeasurement of the 50 'lux-a. Eather is sending me the data and I will post his measurements of my lenses. For the most part these three specimens measure better than the published specs. How nice Leica is conservative rather than blowing smoke at us.

 

There IS a 15mm f2.8 R-lens. How 'bout Leica makes an M version of this lens?

 

It would be nice. Look at the distagon vs CV 15mm difference. It Could be the biggest lens in the lineup after all the coorections, maybe 12-15 elements in 10-11 groups!

[marknorton]

You'd think the R lens would be a good starting point, but look at the price...

[wparsonsgisnet]

Advertisement (gone after registration)

I put my money where my mouth is. Zeiss gets $3800 for theirs (Popflash and B&H). I prefer the way Leica draws images and want such a lens.

 

Gimme the lens. I only hope I can get one before Guy buys them all up.

[fernando_b]

>> he said that the manufacturers could certainly build the lenses so they didn't vignette

 

Bill,

if he means that the design can be made so well to avoid additional falling of brightness beyond what is required by physical laws, well this can also be true. But some of it is imposed by the fact that the iris is fixed in plane: to avoid vignetting totally requires a iris not plane, moving during the shot and also a curved film (or CCD sensor), do you imagine the mess?

 

>> and a transmission factor of .93

This means that lens is excellently designed!

 

Fernando.