p.3 #1 · 17-55mm f/2.8 IS USM or 24-70mm f/4L on a 7D?
saaketham, wonderful colors in those pics. thanks for the 'real-world proof'.
btw, I just realized I mistyped 24-70 f/4, instead of f/2.8 when I started the topic
I was trying to assess how important the IS is, and video is really driving it home, but still, I want to ask:
- How long do you have to give to IS before snapping away? IE: Time between half-press and full on the shutter.
- I have disabled the focus on the shutter, so I focus with AF-ON, but for IS, this is a bit impractical with IS I am thinking. I find myself pressing the buttons at the same time since you don't want wait for IS twice. (yes this is a bit stretch..)
- for fast moving subjects, ie kids, in low light, can't really slow down the shutter below 1/50 or so. Does the IS matter for the short focal lengths of the 17-55 or 24-70 at that? I would love to get feedback.
p.3 #2 · 17-55mm f/2.8 IS USM or 24-70mm f/4L on a 7D?
jrscls wrote:
My point is, that if you want an equivalent of 15-55 f2.8 going from 1.6 crop to full frame, the 24-105 converted would be approximately 15-66 f2.5 (field of view and depth of field) so it should meet your needs.
No offense but nothing you said above makes any sense.
p.3 #3 · 17-55mm f/2.8 IS USM or 24-70mm f/4L on a 7D?
Burak Baysal wrote:
saaketham, wonderful colors in those pics. thanks for the 'real-world proof'.
btw, I just realized I mistyped 24-70 f/4, instead of f/2.8 when I started the topic
If they sold a 24-70mm f/4 for $500, that'd be awesome, along with the 70-200mm f/4 for those on a budget.
How long do you have to give to IS before snapping away? IE: Time between half-press and full on the shutter.
I have IS turned off most of the time on my 17-55. I only turn on IS when shooting in vbery low light. Otherwise, I have reasonably steady hands, and I want longer battery life and also read a few reports of the IS on this model going out too soon or something. Either way, I don't use IS more than 10% of the time. But, your concern about video .. now that'd be a good use for the IS. Haven't tried that yet on my 7D .. video.
p.3 #6 · 17-55mm f/2.8 IS USM or 24-70mm f/4L on a 7D?
jrscls wrote:
Simply converting the 24-105 on full frame to a similar field of view and DOF on 1.6 crop.
You are confusing a few people here. An f/2.8 lens will always be an f/2.8 lens, just as an f/4 lens will always be an f/4 lens REGARDLESS of sensor size. Apparent DOF is another story entirely. A 24-105 APS-C equivalent would be a 15-66 f/4...not f/2.5.
p.3 #7 · 17-55mm f/2.8 IS USM or 24-70mm f/4L on a 7D?
I agree f2.8 is f2.8.... however, I made it very clear I was factoring in field of view AND corresponding depth of field. Yes it is confusing, but you can't ignore the differences in depth of field across formats. I see it all the time in forum posts, so this isn't anything new here.
M Vers wrote:
You are confusing a few people here. An f/2.8 lens will always be an f/2.8 lens, just as an f/4 lens will always be an f/4 lens REGARDLESS of sensor size. Apparent DOF is another story entirely. A 24-105 APS-C equivalent would be a 15-66 f/4...not f/2.5.
p.3 #10 · 17-55mm f/2.8 IS USM or 24-70mm f/4L on a 7D?
The depth of field only changes for a given lens and focal length when the distance between the subject and camera changes. It has nothing to do with the sensor size. People confusingly believe the larger sensors give you tighter dof, when in actuality, you have to step closer (or zoom farther) to fill the frame. That is what causes the the tighter dof, not the size of the sensor. If you put the same lens on a 1.6x crop and a FF, and set them to the same FL, and the same distance to subject, you will get exactly the same dof. If you want tighter dof on a crop sensor, just get closer or zoom in more.
No offense but nothing you said above makes any sense.