Re: 800-1200mm telephoto lens - good enuff for Tikaboo?

Message posted by gary on May 28, 2002 at 21:06:20 PST:

I shoot fuji Provia 100F, which is iso 100. There is no finer grain color film. Your questions sounds like it is related to photographing airplanes rather than the base from Tikaboo. When shooting airplanes, I generally force the camera to think the film is a bit faster. [Of course, this is when I remember to do so.] Generally planes will have some surface that will cause a specular reflection, so I rather underexpose a bit to prevent washed out parts of the photo.

For Tikaboo, I started out shooting TMY (iso 400 black and white film). Originally I thought this would be needed to get around the shake of the camera due to the wind conditions at the peak. However, I now shoot TMX (kodak iso 100 b&w). This is because the TMX grain is much smaller than TMY. I would need about 3 more paragraphs to explain why the dynamic range compression of TMX aids in the photo, which I why I really should just write up a webpage, perhaps with comparisions of different films, telescopes, etc.

More relevant to Brian's question, the last time I photographed the base, I used Joerg's C5 with my baush and lomb 2x telebarlow. We fiddled with a 3x barlow, and even stacking 2x barlows. However, IF you can focus the camera AND shoot fine grain film, I see little advantage to getting more magnification. I'd say an equivalent focal length around 2000mm if fine for Tikaboo. Similar to radio reception, the front end is the biggest factor determining photo quality. If the basic lens is crappy, the telecoverters (barlows) will just amplify the crap. Note that there are disadvantages to getting more magnification. For instance, for a given lens, putting a 2x telecoverter in the path will reduce the light by a factor of 4. Now you are more prone to shake. Now you have twice as many photos to stitch together to make a panoramic.

What you are really trying to do is to get the image projected on the film plane to a size where the lens is the determining factor of image quality, not the film.

Steve of pointed out to me that you really need to practice someplace locally to perfect your long distance technique before lugging all that gear up Tikaboo. Joerg and myself drove to the top of Mount Diablo and practiced taking photos of Travis AFB. It turns out that the distance is about the same as Tikaboo to Groom. If you don't have a military base and a mountain handy to shoot, go for a mountain and a commercial airport. If you get photos of both jumbo jets and props, you will get a feel for the difficulty in photographing Groom. If you don't have a mountain or high place to view the base, you are at a great disadvantage. The air near the ground is very turbulant. You don't want the entire photo to be dominated by ground level air. [Note that this becomes very evident when taking photos of the radar gear near the north gate. There is no high point to take a photo, thus the air near the ground will blur the photo very soon after sunrise.]

In Reply to: Re: 800-1200mm telephoto lens - good enuff for Tikaboo? posted by Hank on May 28, 2002 at 15:03:28 PST:


[ Discussion Forum Index ] [ FAQ ]