Jimmy Ho
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 p.1 #16 · 24-105 f/4L IS vs. 24-70 f/2.8L | |
Rick Ethuen wrote:
After spending time on FM over the past year I realize I have much to learn, so please be patient. This is probably a basic question, but I am not clear on the answer and have not found it in the many threads I have read regarding comparisons of these two lenses. I understand the low light advantage if shooting at f/2.8, but what if any advantages does a f/2.8 lens have over the f/4 lens if you are shooting at f/4 or higher? In low light, can the IS make up for the f/4 with longer exposure compared to the f/2.8. I am deciding between these two lenses. My top priority is image quality. The reach of the 24-105 as a walk around is appealing, but the sense I get from reading threads is that the 24-70 produces better images in the same hands. I currently have the 40D with the kit lens(28-135 f/3.5-5.6), a 70-200 f/2.8L IS, and want to upgrade from the kit lens. Photographic interests at this point center around family, sports, travel and landscape.
Any input is appreaciated....Show more →
In all truth, it doesn't really matter. Pick one you're happy with and spend more time shooting than thinking about which to buy. Both are great lenses and as long as you do your part, are capable of good image quality.
To specifically answer your question:
In low light, can the IS make up for the f/4 with longer exposure compared to the f/2.8.
There's two answers to this - the answer of which depends on what you are photographing. If your subject(s) are still (such as buildings, columns, inanimate objects etc) than IS would be more suitable, as you wouldn't be as concerned with human movement. In this case, IS, with it's 3+ stop advantage can achieve the equivalent exposure as a f/1.4 lens (3 stops greater than f/4).
However, if you are photographing live subjects who move and breath, then you're most likely better off with a the f/2.8 lens, which allows you to shoot with twice the ambient light. The reason being that human subjects can and do move and cause motion blur, and the IS advantage simply will not help you with this. 1/60th is about as slow as you can hold and still get reasonably sharp images of humans being fairly inactive. You may be able to get away with 1/40th or 1/30th or even slower if they are absolutely still and "freeze" for you to take their picture, but I would not count on that. There's always some person that will not stay still (and if you're like me and photograph weddings, kids etc, you'll likely find a faster shutter speed to be easier to work with). If in doubt, use a higher shutter speed, larger aperture, and boost your ISO.
Much of the actual differences between the two lenses can be bridged with correct use of flash. If you're photographing groups, you may not want to use f/2.8 anyway due to its shallower depth of field, and may in fact stick with 1/60th, f/4 or f/5.6. In this case, it woudn't really matter which lens you use to create the image.
The human movement at 1/60th idea can also be broken with flash as well - if your background is lit with ambient and your flash only falls on your subject, you may be able to use a much slower shutter speed, as your flash will freeze your subjects quickly.
So, like I said before, it doesn't really matter lens you use. Pick one you're happy with and spend more time shooting and thinking about shooting than thinking about which to buy. Both are great lenses and as long as you do your part, are capable of good image quality.
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