A bit dated but here you can learn how the focusing system works in a DSLR. Your lens choice greatly impacts the focusing speed and accuracy, especially in low light.
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Wedding and Event Photographers 28-70 f2 or 24-70 f2.8 IS?
- Thread starter Photo Hack
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A bit dated but here you can learn how the focusing system works in a DSLR. Your lens choice greatly impacts the focusing speed and accuracy, especially in low light.
Photo Hack
Just to be fair:
a camera that is rated by manufacturer for -5 EV AF sensitivity should deliver a similar AF performance with F4 lens attached VS a camera that is -4 EV rated with a F2.8 lens attached. 1 stop of light difference in either case.
Just FYI, Privatebydesign is a very experienced and technically versed shooter. It may be a specific condition or firmware related issue but still worth your attention.
Just to be fair:
a camera that is rated by manufacturer for -5 EV AF sensitivity should deliver a similar AF performance with F4 lens attached VS a camera that is -4 EV rated with a F2.8 lens attached. 1 stop of light difference in either case.
Just FYI, Privatebydesign is a very experienced and technically versed shooter. It may be a specific condition or firmware related issue but still worth your attention.
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Sounds logical but that’s not how it works. You ever look at the footnotes in those specs? Here’s some right on the Canon website. The internet is rich and full of information for anyone who wants to learn how Canon sensors work and their relation to lens choice.
I’m not here to educate people, just pointing out the comparison isn’t a good one by any means. A lot of logical fallacies involved in this discussion.
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You’re inferring that one Stop of light loss from a lens is the only consideration to these values. What about limitations of cross type points? Accuracy? Detection? Speed?
There are a high number of variables involved in “AF performance”. If you dig into real scientific analysis in lens relation to sensor you’ll see why Canon leaves a vague footnote next to these specs.
Within that first footnote is a world of information you can dive into if you would like to dig through....but it’s probably not worth anyone’s time. It’s better to conclude , in my opinion, that the comparison isn’t valid and should be taken with a grain of salt. Lens choice has a major affect of AF performance...and is still only one variable among many. Af drive mode? Subject? Lighting? Temperature? Point type and selection? Firmware? Etc. etc. etc.
Look up some discussions related to teleconverter limitations and affects on your focusing. You’ll see a major dramatic affect on AF performance when you change the physical characteristics of a lens on the same body.
There are a high number of variables involved in “AF performance”. If you dig into real scientific analysis in lens relation to sensor you’ll see why Canon leaves a vague footnote next to these specs.
Within that first footnote is a world of information you can dive into if you would like to dig through....but it’s probably not worth anyone’s time. It’s better to conclude , in my opinion, that the comparison isn’t valid and should be taken with a grain of salt. Lens choice has a major affect of AF performance...and is still only one variable among many. Af drive mode? Subject? Lighting? Temperature? Point type and selection? Firmware? Etc. etc. etc.
Look up some discussions related to teleconverter limitations and affects on your focusing. You’ll see a major dramatic affect on AF performance when you change the physical characteristics of a lens on the same body.
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for simplicity let's consider the central all cross dual cross AF point only and all the rest being equal for simple focus and recompose method. .. I am aware of the conditions you are referring to and certainly well aware of focusing system limitations, no need to discuss basics. however what Private has mentioned is alarming to me as he is well aware of the same and able to judge AF performance of a camera based on years and years of professional experience.
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I can appreciate that but I think the obvious answer is comparing a dual processor camera that costs three times more with a f2.8 telephoto lens vs an f4. The EV-5 spec on the R isn’t the only factor here in this situation.
What would you expect comparing a 5D4 with the 70-200 vs a T7i and Kit lens?
Here’s the specs from a t7i. I wouldn’t expect it to perform as well as the 5D in the above example in the real world EV-3 isn’t the only spec that’s different.
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Even when IBIS is available, that loss of 4mm would bug me. And I think I could just use my current ef 24-70mm f/2.8L II. But it would be a tough call with IBIS!
True that switching lenses during some events is no fun. Carrying two cameras, especially with lenses as big as the 28-70mm, doesn't seem too fun either!
Good poll, btw!
True that switching lenses during some events is no fun. Carrying two cameras, especially with lenses as big as the 28-70mm, doesn't seem too fun either!
Good poll, btw!
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Ronny Wertelaers
Ronny Wertelaers Photography
If a moment is happening with you're zoomlens 28-70 zoomlens, is it on 28mm or on 70mm when the moment is happening? So you first need to correct this and change it on 35mm for good impact. So you have to take a extra step before you can take the shot with the risk of losing te moment. With a fixed 35mm you need to be close, you're pictures will have more impact and you learn to quickly stand at the correct distance because you know this lens so much. So i think with fixed 35mm you can have more and better moments and can help you to become a better photographer.
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