Speed or IS; which is most important?

Discussion in 'Digital Photography' started by harrycobbold, Jun 4, 2011.

  1. macrumors member

    I've got a Canon 7D, and I'm looking to pair it with some nice glass: Telephoto, probably 70-200mm, USM with a nice low f/stop. My problem is that I just can't afford an f/2.8 with IS, but am not too keen on having a much higher aperture.

    I'm buying this lens all most entirely to photograph motorsport, so obviously shutter speeds will be above the focal length, which means I won't need IS right? But, I get that horrible feeling I'll regret it once I've bought the lens. So basically, how good and how important is IS too a lens since I have no experience with IS?

    Thanks, Harry.
  2. macrumors 68040


    Unless you plan on using a tripod, monopod or have insanely steady hands IS is an important feature to have on a long, heavy lens suchs as a 70-200.
  3. macrumors regular

    IS is something that if you've never had it you could go on forever and never miss or need. Once you've shot with a GOOD lens with IS it is a little hard to go back.

    One thing is the overall build quality of the lens and sharpness of the lens is generally going to be better with an older pro-level fast telephoto lens than with a newer slower IS lens.

    Get a good mono-pod and quality ball head and IS should be a non-factor for the shutter speeds you would most likely be using.
  4. macrumors 65816


    It depends on the IS. Canon's IS is rated to allow four stops slower photos to be taken. In my experience, that's pretty much true, it does wonders. Because of that, you can have an aperture four stops smaller than the non-IS camera and still get the same sharpness on the photo in terms of shakes. If you plan on photographing sports though, the faster shutter speed will be better.
  5. macrumors member

    So therectically using a f/4 stop lens with IS on is the same as using a f/0 lens with no IS? That would make a lot of sense to save money on speed and get a f/4 with IS! Would that be right?
  6. mackmgg, Jun 4, 2011
    Last edited: Jun 4, 2011

    macrumors 65816


    Well almost, four stops below f/4 is f/1. So shooting f/1 and f/4 would get the same blur from camera shake. That being said, the IS just reduces blur from shaking at a lower shutter speed, it does not increase the shutter speed. f/1.4 would still have a faster shutter speed and be better at capturing motion.
  7. macrumors 6502

    I have a 7D and a 70-200 non IS f/4 L.

    I wish I had plumped for the IS version! Obviously it would be very nice if it was faster, but using this lens at the 200mm end is VERY difficult unless you use a tripod or have a very faster shutter speed. Obviously with only f/4 that's not always possible on all but the very brightest days.

    I can compensate a little with iso, and luckily the 7D in low light is pretty good. Also, the quality of the L glass I'm using helps too. I'm not sure about 'lesser' lenses though.

    I brought it for snowboarding shots, and I don't really want to carry a tripod up the hill all the time!!

    That said... the lens rocks!!
  8. macrumors member

    What would you recommend then, EF 70-200mm F/4.0 L IS USM or a EF 70-200mm F/2.8 L USM because they have roughly the same price, but can't I can't decide between the features!

    Also, can you fit a canon extender to both of them?
  9. harrycobbold, Jun 4, 2011
    Last edited: Jun 4, 2011

    macrumors member

    I've heard that it gives seriously crisp results! But I'm in the same boat, I don't want to be carrying a tripod round with me, how is it at isolating the subject, i.e. Does it blur the background well?
  10. macrumors 6502

    Yeah, the fact it's not very fast doesn't seem to matter to much with background blur and bokeh.

    Ideally, I would like the top of the range f/2.8 IS version (trés expensive!!) but with hindsight I should have saved up the extra 300 quid and got the IS version of mine.

    That said I am entirely happy with the lens, and like I said in the above post, you can use some tricks compensate for increasing shutterspeed.

    The images it produces are very impressive.

    Go into a shop and snap some shots on it at the 200mm end and your'll see if you can deal with it or not.
  11. macrumors 65816


    With telephoto, even higher apertures will give a pretty good bokeh. I have an old Canon FD mount 70-210mm f/4.5-5.6 and even at f/5.6 the background is completely blurred for most shots.
  12. macrumors member

    Haha, yes, I certainly wouldn't mind that version at all... The price is probably higher than the mountains you climb up to shoot though!

    I think that may well be what I go for in the end then, sacrificing a bit of speed for the IS version of the lens, what I'm really excited about though is the shear quality you get with canon L lenses!
  13. macrumors 6502a


    You stated in the original post that you are photographing motorsport. So you are taking pictures of rapidly moving objects, right?

    IS only compensates for camera shake, it does NOTHING to freeze moving objects. If your goal is to freeze action on rapidly moving objects, then IS will NOT help you. You need a fast shutter speed. You can get that either through raising the ISO or opening up the aperture. Higher ISO will introduce grain, larger apertures will blur the background and potentially introduce issues with focus (if you don't nail focus with a wide aperture on a long lens then the image will be blurry).

    IS is a crutch to enable you to handhold at shutter speeds that should require a tripod. But if you really need a fast shutter speed to creatively capture your image, then IS isn't going to help you.

    For static subjects, IS is great and can offset a slower lens. For dynamic subjects, you need a fast enough lens to enable the short shutter speeds needed to freeze motion.
  14. macrumors 6502

    Yeah.. you will LOVE it, whichever you get!! Can't wait to see some shots when you have purchased it!!
  15. macrumors member

    Very good point, and what I'm asking, but others seem to reckon that if I want shoot this stuff handheld, with such a heavy long lens, then movement of the camera is going to happen, and therefore IS needed, but say you have a quick shutter seed, does that cancel it out?
  16. macrumors 6502

    But when you shoot at 200mm, you get a large amount of camera shake unless you can shoot at 1/1000 or higher.. so it would help.

    Also like you said, he will more often be needing to shoot at smaller apertures anyway because of dof issues.
  17. macrumors 6502

    You can cancel camera shake out by making sure your shutter speed is above the focal length of which ever lens you use.

    ie 200mm=1/320 or higher (taking 7D sensor size into consideration)

    This, however, doesn't necessarily translate in real life situations.
  18. macrumors member


    I think the Canon EF 70-200mm F/4 L IS USM seems like the best compromise of price and features, looks like there are some pretty good second hand offers on it as well!
  19. macrumors 6502

    I agree, you'll be very happy I think!!
  20. kallisti, Jun 4, 2011
    Last edited: Jun 4, 2011

    macrumors 6502a


    For moving objects, the most important element will be choosing the appropriate shutter speed for the effect you wish to achieve. If you are trying to freeze your subject, then the necessary shutter speed will depend upon the speed of the subject and whether it is heading towards you or whether you are shooting it passing by you. These variables will dictate the shutter speed the image requires. The presence or absence of IS on a lens doesn't impact this "necessary" shutter speed.

    Once the correct shutter speed has been determined, then you have to determine the correct aperture and ISO to get a proper exposure. Lower ISO will usually give better detail, contrast, and less noise. The magnitude of the effect of ISO depends on the camera/sensor. Aperture choices affect DoF (with the added "gotcha" that larger apertures make focusing errors more obvious).

    Available light dictates which aperture and ISO choices are viable for a given shutter speed.

    If your image requires very fast shutter speeds, then camera shake becomes less of an issue, even with a long lens. This obviously depends on the shutter speed that your image requires. As pointed out earlier in this thread, the usual rule-of-thumb is that you can shoot handheld with a non-IS lens at speeds equal to 1/focal length. So for a 200mm zoom, that would be 1/200th of a second. If you are shooting at 1/500th of a second or faster, then camera shake shouldn't be an issue....

    If your image requires shooting at 1/500th of a second or faster, I'm not sure how much IS actually going to help you. As stated above, at these fast shutter speeds you don't need to concern yourself with camera shake. You may very well need a large aperture to attain correct exposure at 1/500th of a second, depending on available light. Or you may need to bump the ISO. But "camera shake" per se shouldn't be an issue.

    What's more, in bright daylight, a "slow" consumer lens may be fast enough to freeze even quickly moving objects. With strong light you may be able to achieve the necessary shutter speed with a "relatively" slow lens.

    For shooting fast-moving subjects, IS isn't all that great. Sports photographers aren't spending the big money on fast lenses because they like carrying around heavy glass and have money to burn. They do it because there isn't another option that allows them to capture the images they want/need in the lighting situations they find themselves in. IS isn't the answer, fast glass is. Depending on the specifics of your intended shooting, I'm not sure that IS is going to be that useful to you. IS is great for some applications. Sports photography isn't one of them.

    The best answer for you would be to rent both of the lenses you are considering. Shoot with both and see which one allows you to capture what you want. If the slower lens with IS works, then great. If you need the faster lens, then great. But at least you know what you really need before you buy.
  21. macrumors 6502a


    100% agree with Kallisti
  22. macrumors 68020

    IS helps against camera shake, but not motion blur. The longer the focal length, the faster the shutter speed needs to be if you want to freeze motion and avoid motion blur. Hence, a faster lens will allow you to shoot at faster speeds (or at lower ISO), a feat that IS doesn't give you.

    Besides, I don't think the 70-200 mm f/4 IS is that great a deal (the non-IS version is a steal).
  23. macrumors 6502a

    Have you been to a shop and actually held each lens in your hands? There is a HUGE difference in the handling, size, and most importantly, weight of the lenses. After messing with the lenses for about 10 minutes in the store, I decided that if I ever upgrade to the 70-200 line, I will almost certainly go for the f/4 IS.

    That being said, if you NEED f/2.8, no amount of IS is a substitute. Only you know if you need it for motorsports.
  24. macrumors 65816

    Get the 2.8 without IS. The extra stop will not only give you higher shutter speeds, but it will also give you more flexibility in image creativity.

    I have a 24-105L f/4 lens. It has IS on it, but I rarely have it turned on. It drains my battery quicker and if you expose correctly or use a tripod, I don't find it to be that big of a deal.
  25. macrumors 65816

    While IS can be of help in some situations, also realize that there is a practical range of shutter speeds over which it is effective.

    Anything around 1/2 sec or slower isn't going to be "fixed" by IS. Over that timescale, natural human hand shake is just too great for IS to compensate (i.e. the amplitude of the total shake overcomes the limit of IS to correct). Obviously YMMV as everybody's hands are different but it's a pretty reasonable rule of thumb.

    Also, I know that Nikon's VR system samples at about 1kHz. I don't know what it is for Canon, but probably can be assumed to be similar. That means, around 1/500 or so SS, IS loses effectiveness, because it is only taking 1 or 2 readings throughout the duration of the exposure. Note that this limit is independent of FL.


Share This Page