[GreenKeys] off-topic: advice on photography and camera lenses

[gil smith]

Hi Bob:

In the "typical" gym lighting I have found so far, in three different 
gyms, I have needed to set ISO to 12800 in order to get about 1/250 
sec or better with my f5.6 lens (at 135mm zoom).  Pretty grainy 
(color noise) pics, but still better than I had before.  If I drop 
ISO to 6400, it is still kinda noisy.  At 3200 they start to look 
pretty decent, noise-wise, so that is my target speed.

I need to drop two stops and get at least down to an f2.8 lens, so 
this number is driving my lens search.  An added benefit is blurred 
backgrounds (as the gym walls are covered in posters and crap), but 
this is a secondary consideration.  Now f2.8 won't blur as much as 2 
or 1.8, of course, but it will sure help over my current f5.6.  And 
with 2.8 I will make less manual-focusing errors than 2 or 
1.8.  Yeah, I can blur backgrounds in photoshop, and would if I had a 
shot worth the time, but it is nice when an open lens provides that for you.

Anyway, f2.8 zoom lenses are just way too pricey, so I just ordered a 
200mm f2.8 fixed telephoto -- hopefully it will do what I am looking for.

Thanks to everyone who replied on and off list with helpful suggestions.

gil


At 05:06 PM 10/28/2008, Bob McConnell wrote:
You need to work out some basic math for your choices. One more 
F-stop will allow you to cut the effective film speed in half, or cut 
the exposure time in half. Cutting the exposure time in half requires 
twice the film speed. From there you can figure out what your optimum 
trade off is going to be. The price of the lens will probably define 
your upper limit, but at least you can work out the effective range 
of options you have to work with.

>Bob McConnell
>N2SPP



Vaux Electronics, Inc.
480-354-5556
(fax: 480-354-5558)
www.vauxelectronics.com