A lens/shutter combo for B&W aerialsgreenspun.com : LUSENET : Large format photography : One Thread
Does anyone know of a coated 300mm lens f6.3 or faster that can be found in a reliable shutter that can do 1/225 or 1/250 AND cover 8x10 thats sharp all the way out to the edges? My Nikkor M 300mm f/9 in it's copal#1 is an excellent lens for color, but if I use any kind of a filter for B&W my negatives come out too thin. I could push the film---I'm shooting Tri-X @ 320 and T-max @ 400---but I'm paranoid of grain(a 35mm days flashback, I suppose) as I want to enlarge to 40"x50" max for a museum display. Thanks for any and all suggestions!
-- John Kasaian (email@example.com), May 26, 2002
If your negatives are too thin when you use a filter for B&W, the problem is probably related to an incorrect filter factor. The lens itself would not be the problem.
-- Ken Burns (firstname.lastname@example.org), May 26, 2002.
The filter factor is really the problem. Any filter factor I use requires a slower shutter speed than 1/225 and the image gets blurred because of the motion of the aircraft. The weakest filter I've used is a #8. I can try a weaker filter I suppose. though in Steve Simmon's book Using The View Camera, no exposure increase is recommended for the #8 filter(p.28.) Are any developers noted for increaseing density in thin negatives? That might be worth a try however experimenting with aerial photography is rather expensive. At least in the winter I can take a ski lift to altitude---lots cheaper than renting an airplane.
-- John Kasaian (email@example.com), May 26, 2002.
John, the Nikon 300m f9, in the Copal 1 shutter, is as good as it gets. Anything faster is in a larger shutter and will require larger diameter filters. Of course, you are already aware of this. I suggest that you switch to Ilford HP-5, developed in Ilford Microphen 1:1. The #8 filter requires, at least, a 2/3 stop increase, and the #15 needs, at least, 1 stop, for use with HP-5. Also, HP-5 can be rated at a true 400 speed if developed in Microphen.
-- Eugene (TIAGEM@aol.com), May 26, 2002.
All the 300mm F6.3 lenses I am aware of like the Commercial Ektar and the Schneider Xenar are mounted in Acme#4 or Copal or Compur #3 shutters whose fastest speeds are 1/125 sec.Lenses of this size and larger won't fit in the smaller shutters with the faster shutter speeds.If they could the demand for your Nikon M,the Fuji C's,and the schneider G-Claron would'nt be so great.
-- asher galloway (firstname.lastname@example.org), May 26, 2002.
Your interest in a 300mm lens brings to mind some aerial photograph know-how I got flying over 2800 air hours doing photo recon for the Navy Fleet Intelligence Center. The lenses we used were B&L Tri Metrigon system lenses that were calibrated to four decimal places and engraved on the lens mount. i.e. 12.0034". If your interested in razor sharp aerials....try to find some surplus Basch & Lomb Tri Metrigon lenses. These were serious pieces of glass...even by modern day standards. Richard Boulware _ Denver.
-- Richard Boulware (email@example.com), May 26, 2002.
This might be another way around the problem....have you thought of trying Tri-X aerial film?
The closest size would be 9 1/2" roll film so you'll lose a little on the ends. It's easy to cut down and use in film holders and has higher contrast than conventional film and extended red sensitivity. I use it it Cirkut cameras and the contrast takes a bit of working around for pictorial work.
The only aerial film I have on hand is Plus-X 2402, this is what it says in the product info for exposing it.
TYPICAL CAMERA EXPOSURE
Based on processing to an Effective Aerial Film Speed (EAFS) of 160, a typical exposure for 2402 film is 1/500 second at f/11. This exposure is based on the following conditions-a solar altitude of 40 degrees, an aircraft altitude of 5,000 feet, and a clear day.
-- Clayton Tume (firstname.lastname@example.org), May 26, 2002.
Why don't you try contacting Kodak Aerial Imaging? i'm sure they'd be happy to help.
-- Mark Sampson (MSampson45@aol.com), May 28, 2002.
Thank you all for the excellent advise. I'm waiting for a calculator Kodak is sending me to work out aerial exposures. I'm going to do a series of exposures without using any filter just to see how they turn out. My subjects are granite, ice, snow, and clouds againt a usually clear,very deep blue sky. It would be interesting to see the diferences between HP-5+ and T-Max 400 in this enviornment. As far as cutting down aerial film, it is so expensive that it would be worth getting an old K-17 K-18 or K-19 and shooting it in rolls with a focalplane shutters and a trimetrogon lens. Of course I'd have to find a processor for 9 1/2" film( 3 bath tubs?) FWIW, check out http://pws.prserv.net/varney/20cms/cameras.htm Thanks again!
-- John Kasaian (email@example.com), May 28, 2002.
Try a #3 filter. Less haze cutting but a factor about 1.5 rather than 2. Also can somebody explain aerial film speed vs ASA (now ISO)?. It seems, by reading Kodak info, that Aerial Speed is figured at a very high contrast index. If so, longer developement might work to increase contrast and apparent speed.
-- Ed Workman (firstname.lastname@example.org), May 28, 2002.
I'd at least consider a 240/9 Fuji A. Added sharpness and contrast by the extra speed of the Copal 0 (1/500 & 1/250) and multicoating might well overcome the extra enlargement necessary to get to the same image size as a 300 will give. After that I'm a diehard 305 G-Claron guy. I haven't had the pleasure of using a 300 8.5 Fuji C but it would be Multi-Coated and in Copal 1.
-- Jim Galli (email@example.com), May 28, 2002.
Ed:I just got the Kodak Aerial Exposure Computer in the mail, heres the qoute:"Effective Aerial Film Speeds(not to be confused with conventonal film speeds which are designed for pictorial photography) for black and white negative aerial films are based on 3/2H, where H is the exposure(in lux seconds) at the point on the characteristic curve where the density is 0.3 above base plus fog density." Jim: The Gowland camera I'm using has a built in lens cone(well, actuallly the whole camera is the lens cone!) and will only take a 300 mm lens. I could try shimming for a 305 G-Claron, but at f/9 I'm afraid I'd be at the same point I am with the Nikkor M(and besides, if I had a G- Claron, I'd want it on the 'dorff to take advantage of that nice image circle!). The 240mm Fuji might fit the 5x7 model of this same camera---that might be worth looking into. Thanks again for all the advice!
-- John Kasaian (firstname.lastname@example.org), May 31, 2002.