TRT convertible!

[Jim Fitzgerald]

I was checking out this fine lens the other day and I got to wondering about it. I bought another front component from Jim Galli. It makes this lens a 14". The standard configuration I have is 12,21,28. I get confused easily, so here is my question. How many possibilities do I have. The component I got from Jim says that the rear FL is 25". I've always wondered if you can use the single component on only the rear or can you use it on the front? My inquiring minds needs to know. Can the lens experts please set me straight. Thanks.

Jim

[Gene McCluney]

"Normally" speaking a "convertable" lens can be used with either front or back elements, or both elements together. In some cases when using only the front element, it is advisable to screw it into the back of the shutter, for maximum sharpness. The elements used alone will not produce an image as good as both elements together.

[Jim Fitzgerald]

Gene, thanks. I have always used the single component on the back with a yellow filter. The 8x10 images I've made make nice contact prints. Just curious about the different possibilities I have with this lens.

Jim

[eddie]

i havea 12-20-25. how do we both get 12 inches combined?

i need to keep a look out for some more elements.

i shot mine the other day at 12 and 20 (with a yellow filter at 20) and the pics are wonderful. it looks like i got a good copy.

keep us posted.

eddie

[Vaughn]

I made a nice shot with the 28" element on the back with a warming filter (had no yellow filter). The neg (8x10) made a nice platinum print, but wasn't razor sharp like I like for carbon printing. Anyone notice any significant focus shift when using a single element?

Several years ago I used the 28" element on the back to photograph a lunar eclispe as a series of exposures on a piece of film as it left totality -- with no filter on front. On the 4th exposure, the cold air kept the shutter from closing so I ended up with three shots of the growing moon, then a long white streak. So it goes...

Vaughn

Taken with the 28" element on the back...

[Michael Roberts]

Jim,
Try this:
http://photo.net/large-format-photography-forum/00352X

Seems like you also have a shorter than 12in combo with the 25/21 pair (haven't done the math--10in?).
Fun!
-Michael

[Jim Fitzgerald]

Vaughn, I see what you mean about the soft edges. I guess it depends on the look you want. Everyone's vision is different. Nice shot by the way! Everyone needs to have one of those in their collection.
Michael, thanks for the link. My lens says on the front of the barrel and the aperature ring that it is 12" FL. Who knows?

Jim

[Turner Reich]

It's a 12" with the elements combined. Use a filter to focus with a single element.

[Jim Fitzgerald]

It's a 12" with the elements combined. Use a filter to focus with a single element.

It says that it is a 12" so I have to believe the maker. I always use a yellow filter when using a single component. Nice to hear I'm doing something right.

Jim

[Vaughn]

...snip...Everyone's vision is different. Nice shot by the way! Everyone needs to have one of those in their collection....snip
Jim

Yeah, I know what you mean. I resisted making that cliche image for a long time...but thought it would be a nice test for the 28" element. Ended up with an image I like, though. Here is an image taken at about the same spot -- different time of day, different year (but about the same time of the year), different lens, same camera -- that I like much better (also a pt/pd print.)

Vaughn