p.3 #1 · F2.8 vs. F4? Is it really THAT signifigant?
you also need to realize this, upping the iso will work, but upping it too much will make your pics grainy. DO you want a really grainy pic when you could have got a smooth pic with a faster lens? I know I dont. Well that is because I do weddings and sports. But still, iso is not that great of a quick fix for a slow lens. I shoot hockey with a f2.8 lens and i even use iso 1600 with great lighting. So just think, if I used an f4 lens with iso 1600 the sutter would be slower or if I bumped to 3200 the shutter would be the same but the grain would be horrible.
Jul 25, 2005 at 08:26 AM
spartan123 Offline • • • • [X]
p.3 #2 · F2.8 vs. F4? Is it really THAT signifigant?
Exactly why I have both.
The Big Bad wrote:
I like having both
for hiking and applicatons such as landscapes where Im stopping down and using a tripod anyways, the f4 is great due to its low weight
for sports and other things where I need to get a minimum shutter speed, the f2.8 is really great to have, and with IS its very useful for places where I cant or dont want to have a tripod
sometimes the difference means getting shots and other times its just carrying a bigger heavier lens around
p.3 #3 · F2.8 vs. F4? Is it really THAT signifigant?
Had the same dilemma a while ago. F2.8 vs F4 vs IS etc. Tried the F2.8 and decided it was a little on the large side and hence i would not carry it. Decided to opt for the 70-200 F4. After using for a while i certainly discovered the limitations of F4 and decided to supplement with some fast primes - 85 1.8 and 135 F2. Don't get me wrong the F4 is a stunning lens and i for one will not be getting rid of mine any time soon. The zoom + prime combo has worked like a dream and my back is thanking me for not having to carry the weight of the 70-200. Eitherway you cannot go wrong with the 70-200's as they are stunning. I will say however when i am looking for the absolute best....the 135 F2 always seems to win the day. So my advice would be add some fast primes to complement your F4 at the focal lengths you really need something faster than F4. You need to look at your own pics and think about how many times have you not gotten the pic you wanted because you needed a faster lens. If you want to do indoor head & shoulder pics then the 85 1.8 is a gem of little lens and if you have a little more room then the bokeh on the 135 F2 will turn you into a prime convert.
p.3 #4 · F2.8 vs. F4? Is it really THAT signifigant?
The f2.8 makes a huge difference...difference between a back breaker and life saver. This is especially apparent at the 200mm long end where you are pushing the limits of the 1/focal length rule.
I just shot an indoor church event last week with no flash, at ISO 1600, and f2.8. I could barely get 1/60...imagine if that were 1 stop slower. BTW, I use the Sigma 70-200 f2.8. If that extra stop is necessary, don't mind the weight, get that Sigma. Its only $100 more than the Canon f4L, and that extra stop is worth the $100.
p.3 #5 · F2.8 vs. F4? Is it really THAT signifigant?
The answer is yes and also no. You can get the same exposure by upping the ISO -- that's the yes part. The no part is this: if you are trying to focus in poor lighting conditions with a lens that still only lets in HALF the amount of light as the 2.8, focus speed is compromised and focus accuracy may also be compomised. Remember that the camera focuses at max aperture, regardless of what aperture the exposure is set for.
kc
Edited by kecohen on Jul 25, 2005 at 05:00 PM GMT (Reason: typos)
p.3 #6 · F2.8 vs. F4? Is it really THAT signifigant?
Yes there is a difference - this question comes up VERY frequently. However mid-range in light and f-stop they are too close to call. Good is Good in either size and configuration.
p.3 #7 · F2.8 vs. F4? Is it really THAT signifigant?
An f2.8 will allow you to use a 2x teleconverter, giving you 400mm. f4 will only allow you to use a 1.4 converter (assuming you want autofocus).
The f4 is considerably lighter than the f2.8, which is also a major factor.
Jul 25, 2005 at 05:11 PM
eosphotog Offline • • [X]
p.3 #8 · F2.8 vs. F4? Is it really THAT signifigant?
Well you has to spend 3 times as much, have a lens thats nearly 3 times the weight and is only 1 stop faster, though with IS in some situations you could say its 3 times faster.
how much weight you wants to carry ? If on holiday you might want to go a bit lighter. Or for the same investment as a 2.8, you could get yourself a few more bits of kit
maybe a 17-40, a 50 1.4 and a 70-200 f4 all for about what a 70-200 IS would be costing you.
p.3 #9 · F2.8 vs. F4? Is it really THAT signifigant?
eosphotog wrote:
Well you has to spend 3 times as much, have a lens thats nearly 3 times the weight and is only 1 stop faster, though with IS in some situations you could say its 3 times faster.
No, it's actually 16 times faster, or 4 aperture stops (1 from lens speed plus 3 from IS). I can regularily shoot at 200mm with 1/30s exposure time and often 1/20s works, too, with the IS. When the IS is on, aperture is f2.8 and ISO is 1600, you don't actually need a lot of light.
One typical situation for such a setup is to take images from a hedgehog that frequents in our backyard. Unfortunately it likes the evening time and shadows of the hedges (no wonder it is called a hedgehog!). Also, it never stays too long in one place and does not give ample warning before appearing, so a tripod does not work. A flash is not an option, either, because it frightens it off. Yes, true that the IS does not stop the motion of the subject, but without it, I would have to add the movement of the camera to the movement of the subject. So I just take a lot of images and 1/3 to 1/2 of them turn to be OK.
This is one of the reasons why I am so happy that I got the 70-200f2.8L IS, even though it is heavy both for my back and my wallet. But it gets me a lot of shots that I could not get otherwise. If you feel this is your situation, then get the f2.8 IS.
p.3 #10 · F2.8 vs. F4? Is it really THAT signifigant?
Bob, seriously, a 2x converter? I have the 70-200 2.8 IS and I only use a Canon 1.4XTC II. The 2X compromises the sharpness too much even in bright sun. What's more, using a converter, not only do you compromise sharpness, you reduce focus speed by something like 60% for the 1.4X and 75% for the 2X (read the information that comes with the converters) so even if your subject is standing still in optimal light, you're going to get seriously degraded performance, regardless of your ISO.
p.3 #11 · F2.8 vs. F4? Is it really THAT signifigant?
Others say only 35% loss of AF speed with the 1.4xTC and double that with the 2X. My own tests w/ the 1.4TC verify this. Since the 70-200IS is one of the fastest (if not THE fastest) focusing Canon, this drop is hardly noticable.
My photos above, taken handheld with the 70-200IS, wide open aperature (f/4) with 1.4TC, though not the sharpest in the world, are still well within the realm of acceptability. And these were all well below the focal length/shutter speed rule. When stopped down a couple of clicks, I get even better results with the 70-200IS and 1.4xTC. In sum, it's a very effective hand held combination which gets me out to 280mm. With the 1.6 crop it seems like about 400mm.
p.3 #12 · F2.8 vs. F4? Is it really THAT signifigant?
No, the 70-200 IS is not the fastest focusing Canon, by a long shot. The 300 f2.8 (IS and non) as well as the 135 f2 beats it cold, but that's irrelevant. Read the documentation that came with your converters. My information comes directly from Canon. Even you say that the 2x converter is double that of the 1.4's 35% loss (reported by "others")--that would still be 70% reduction in focus speed.
As for the "realm of acceptability" for sharpness, wouldn't that depend a whole lot on whose realm you're in and what size you ulitmately want to print the image? Now it could be that I'm just anal, Phil, but I judge a photos' sharpness by the finished print at 300 lpi, not by a jpeg screen image at 72 dpi. I've done so many of them now, that I know when I look at an image just what size it will enlarge to before breaking down.
I have printed gorgeous 20x30s from tack sharp 2.7mp D1H images. This takes some pretty good digital darkroom work and some very fine interpolation software, but it is very doable. In contrast, I won't print anything larger than 9x13 from even my 1D2 shot with a 2x converter on any lens, even the 400 f2.8 IS. It just will not be sharp enough to enlarge as far as I'm concerned--regardless of not having to interpolate quite as much.
This is not a comment or criticism on the relative sharpness of the D1H vs the Canon cameras, but my opinion on the value of using 2x converters in general. I don't use them, and no one who subcontracts with me can use them either, because every shot taken is potentially a 20x30 print.
p.3 #13 · F2.8 vs. F4? Is it really THAT signifigant?
For me, the difference between F2.8 and F4 was not significant enough to justify the extra size and cost of moving to the non IS 2.8 from my 70-200 F4. However, the IS was. The F4 is an excellent lens if you shoot from a tripod or only shoot at high shutter speeds. Hand holding, once you get below 1/400, the 2.8IS is going to start to be sharper and below 1/200, it will be much sharper because of the impact of camera shake. (Same applies to the non-IS 2.8) That doesn't mean that you can't get a good picture from the F4 at slower speeds but if one is comparing the two lenes for "sharpness" in real world conditions, the IS is going to win nearly everytime. For my style of shooting, this is the most important reason for going with the 2.8IS.
p.3 #14 · F2.8 vs. F4? Is it really THAT signifigant?
i am going to purchase the 70-200mm f/4L and the 100mm f/2.8 Macro as well. I am searching photosig and comparing the 70-200mm f/4 to the 2.8 and the 100mm 2.8 to the 135mm f/2.0L and it is a hard decision. Ofcourse the wallet thinks it is an easy decision, lol!
I own film cameras, (20D had an accident w/ a friend...) and 99% of what i shoot is mountains, lakes, waterfalls, sunsets or the beach, etc.(i love Oregon) so i really dont need the larger aperature. I also use my manfrotto tripod ALL the time.
p.3 #15 · F2.8 vs. F4? Is it really THAT signifigant?
Its a bit ironic that the f/2.8 IS is the one that doesn't need a tripod as much, but is quite heavy and large. The f/4 is the one that would benefit from a tripod more, but is light and portable.
p.3 #16 · F2.8 vs. F4? Is it really THAT signifigant?
kecohen said:
you reduce focus speed by something like 60% for the 1.4X
This is not true. It is aboput 35%. My 70-200IS focuses faster than my very fast focusing 135L Even if the 300 2.8 is quicker, (and I do not have one to compare and verify this), I still say that the 70-200IS is one of Canon's fastest focusing lenses. And everything I have heard says it is faster focsuing than the f/4.
BTW I do more than view my images on screen at 72 dpi. The shots I get from my 70-200IS w/ 1.4xTC are tack sharp printed 300 dpi to 8 x 12. That, for me, is within my realm of acceptability.
I haven't tried 20 x 30 but do not see why they couldn't be very nice.
p.3 #17 · F2.8 vs. F4? Is it really THAT signifigant?
I wonder how do people measure the "loss of AF" speed? 35%, 60%?? Did you actually measure the AF speed and is the process repeatable? Are we talking from 1/10 sec to 3/10 sec? What is the reduction in AF speed in a case like that then?
p.3 #19 · F2.8 vs. F4? Is it really THAT signifigant?
Verbatim from Canon's EOS Digital PDF "Getting the most from your EOS-1 Class Digital SLR
Tips and Techniques: Camera Handling & Maximum Image Quality" (page 23):
" ...EF Extenders reduce lens drive speed. As noted in the instruction sheets supplied with the Extenders, the EF 1.4x or 1.4x II reduces lens drive speed by approximately 50~67% depending on the lens in use. The EF 2x or 2x II reduces lens drive speed by up to approximately 75%. This speed reduction gives the AF system more time to detect focus. This is helpful since the depth of focus is reduced with the longer effective focal length and the chance of defocus increases. However, the reduced tracking speed and smaller maximum apertures (that sometimes result in the loss of cross-type sensor focus detection as mentioned in the description of the 45-point Area AF Sensor at the beginning of this document) caused by the use of Extenders can be a disadvantage with fast moving subjects, particularly in low light."
Argue your 35% theory with Canon, they wrote the document as well as the instructions sheets that are supplied with the converters. Does yours say something different from everyone else's? And who are these "other" people who say the speed reduction of the 1.4X converter is only 35% and what makes them more trustworthy than Canon optical engineers?
Since you don't own a 2x extender, why bother to discuss them at all? In your previous post you extoll the virtues of the 70-200 IS with the claim that you can use a 2X to gain 400mm. I questioned the wisdom of that and said that a 2X TC compromises sharpness and focus speed too much--whereupon you then take issue with my paraphrase of Canon's own information regarding their extenders, and particularly the 1.4x....HUH?
Hey, I'm happy you're happy with your 1.4X TC. We're happy with ours' as well. The fact that using one reduces the focus speed as much as it does is not a problem in good light, even for fast moving objects. In poor light, however, we don't use them, either. But we NEVER use the 2X because in our realm of acceptability, which includes 20x30s, the 2x just can't cut it for sharpness even in good light.
p.3 #20 · F2.8 vs. F4? Is it really THAT signifigant?
Sorry, Phil, I apologize for saying you made a claim about the 2x in a previous post. That wasn't you, I realize.
Nevertheless, read the documentation that came with your TC and the other information published by Canon. "...50-67% depending on the lens in use." When you reduce the amount of light by 50% or more, you can (and should) expect your focus to be effected by at least that much. It may be physics, but it's not rocket science.
