EF 70-300mm f/4.5-5.6 DO IS USM - slow

[pfuller88]

I have read previous links and reviews on this lens. Besides the high price, a few people have mentioned this is a "slow" lens. I do not undersand this (I'm a novice), can someone explain what this means to me. I'm seriously thinking about purchasing this lens for my 20D to compliment my Simga 18-125 lens. I take many sports pictures of my kids (need lens speed and higher ISO).

Thanks

[mdr]

The term slow refers to the maximum aperture of the lens. The maximum aperture of the 70-300 DO IS is f5.6 at 300mm. That is two stops slower than the maximum aperture f2.8 of the 300 L IS. In low light conditions, the exposure of 1/125 at f2.8 using the 300 L IS corresponds, due to the maximum aperture of f5.6 of the 70-300 DO IS, to an exposure of 1/30 at f5.6, i.e two stops slower.

Hope this makes sense.

[pfuller88]

Thanks. This helps a lot.

[metsuyan]

Here is some reading on fast & slow lenses (aperture) etc..

It should be quite helpful...

http://www.uscoles.com/fstop.htm

As an owner of the EF 70-300mm I can tell you that if you are taking pictures outdoors during the daytime you should not have a problem and will be quite satisfied with the lens but the major reason for buying it is convenience in that it makes a decent walkaround lens where you wouldn't wan't to lug something big around. If my specific use were to be taking pictures of my kids' sporting events and I wouldnt just be strolling with it walking through interesting enviroments, cities, tourist(lets in more light), I might opt for a faster lens. Its a quality vs convenience dilemna. Don't get me wrong though... the quality of the ef 70 - 300 DO is very very good, but with a 2.8 L lens the quality of photos would be excellent.

You said you need high ISO... this would mean that you are either shooting indoors or at sunset (lower light environments)....
If this is the case I would steer away from the EF 70-300 DO.

Here is another thread I started when I was researching it...


http://photography-on-the.net/forum...ighlight=70-300 (http://photography-on-the.net/forum/showthread.php?t=57768&highlight=70-300)


Best of Luck!

[pfuller88]

Great post on f-stops, I'm moving up the learning curve. You are right on the location, my kids play hockey. I will look at lower stop (faster) lenses which seem to make more sense for me.