Here's kind of an off-beat combo ...
I was playing around with some strange single lens ideas for a "walk-around" lens. Obviously, the 18-250mm f/3.5-6.3 was a good idea ... but what if you already had an 17-50mm f/2.8 zoom ... and really didn't want to add another $450 lens to the pile. What might work?
Why not a 17-50mm f/2.8 and a 2x T/C combo? Now, I'm not a big fan of the Teleconverter, but what the heck ... some folks don't give a care ... they just want an image, to heck with new glass. The constant f/2.8 makes it truly doable without any loss of autofocus at any point during the focal range, you're just doing it at a base aperture of f/5.6 instead.
Let's look at this on the SONY, just for grins. By adding the 2x T/C ... yes, you tend to slow the autofocus response, but not too much. You wind up with a 34-100mm f/5.6 lens. The lens increases in length by about an inch ... and IQ is not too terribly mangled.
Minimum focus distance ... normally 8 inches at 50mm, shortens to 6 inches at 100mm (w-2x), which is kind of an amazing facet to this.
@ 50mm & External ETTL flash
@ 50mm + 2x T/C & External ETTL flash
I mean this is really close-shooting, but it tends to confirm to me that if you are shooting indoors ... six-inches is getting pretty darn close. The MACRO lenses, indeed, get closer ... but, this definitely is a real close-up, Mr. Deville.
Obviously, everything becomes twice as big ... and if you are strapped for room in your "on-the-run" camera bag ... this could be a good fall back idea. If definitely gets you into that "gap" of 50-70mm (short telephoto area) ... that a 70-300mm f/4-5.6 simply cannot manage. You are no darker than 5.6 anywhere in the entire range, either. The 70-300mm 70mm setting meets up with the 2x T/C + 17-50mm lens at about 82mm indicated.
Now, consider a 1.4x T/C ... loss of only one-stop of light ... the focal range goes from 24-70mm and it should become the "perfect" bottom end to the 70-300mm f/4-5.6 telephoto lens, with a base aperture of no more than f/4 throughout the range. Unfortunately, in real life, the 1.4x T/C + 17-50mm lens winds up about 5-8mm shy of the 70-300mm's 70mm setting and is roughly 62-65mm at the extreme long end, but then again ... that's a lot closer than you'd be at only 50mm.
Anyway ... just a few thoughts for beginners trying to make due with the one or two lens bag ... a 1.4x and/or 2x T/C should probably be part of it.
Just a footnote: The 18-200(250)-type and 70-300mm lenses do not play well with T/Cs.
Last edited by DonSchap; 12-30-2007 at 07:09 PM.
- BFA, Digital Photography
A Photographer Is Forever
Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography.
I have a Quantaray 70-300 Macro I tried taking some macro shots. I have a lock on my lens for macro but I cannot get real close. The closet I can get and till focus clear is about 3 feet. Is that about right for this lens. Here are 2 shots I tried.
Be sure to turn off SSS when using a teleconverter too.
Canon EOS 350D, Tamron SP AF 90mm F/2.8 macro, Sigma 18-50mm F2.8 DC EX, Canon EF 70-200mm f/4 L USM, Tokina AT-X124 Pro 12-24mm F4, Soligor 1.7x C/D4 DG Teleconvertor, Manfrotto 724B tripod, Canon Powershot S30