Is a prime lens sharper than a telephoto zoom lens with L glass?

Discussion in 'Canon EOS' started by tuan_quy, Dec 2, 2008.

  1. I currently shoot with the 50d and the 24-105mm L lens. My only complaint has been getting shots in low light
    scenario b/c it's not a fast lens. I hate boosting up my ISO b/c of the noise that I get in the final image.
    Besides that, the image quality, sharpness, and color have all been excellent.

    What I am curious about is the strong following for prime lenses? Would a prime lens that is not an L give you
    sharper images than a telephoto zoom lens that does have L glass?

    For example, I am considering add a macro lens and a prime to my camera bag. I am considering the Canon EF 100mm
    Macro and one of the following primes: Canon 35mm f/2 or the Canon 50mm 1.4.

    Would any of these primes deliver better image quality, sharpness, and color than my telephoto L lens? and if
    yes, which lens should I get since I have a cropped body sensor.

    I am interested in taking indoor/outdoor portrait shots and detail shots that are not all macro work.
  2. zml


    Many single focal length lenses are noticeably better than L zooms and Canon 100/2.8 Macro is no exception: it
    beats the stuffing out of the 24-105/4 L @ 100 mm in terms of sharpness and contrast (even on a full frame camera.)
    Seriosuly - see for yourself: you can compare any two lenses at many f/stops here
  3. No general rule and if you shoot at f1.4 and 1/200 instead of f4 and 1/25 you can expect subject motion blur to affect the sharpness of the pictures you take - offset to some degree by the significant loss in the DOF for the image. The IS of the 24-105mm zoom helps with camera shake but it does nothing for motion on the part of the person you are photographing.

    All zooms compromise IQ but today's zooms can be amazingly good. The Nikon 14-24mm has been shown to produce better quality images than the Canon 14mm prime and the Canon 24mm prime but the Nikon engineers kept the zoom range down to 2:1 which really helps. The Canon 16-35mm f2.8 can also be a relatively good lens and its design also benefits from a conservative zoom range.

    The Canon 35mm f1.4 is an excellent lens and on your 50D provides a normal perspective more appropriate to general photography while the 50mm will be more useful for people. For portrait work with a 1.6 crop camera even a 85mm lens is too long for me and a 100mm (160mm equivalent on a 50D) would be usable only outdoors and then you would still need some distance.

    For indoor and outdoor portraiture I think you would be best served by the Tamron 28-75mm f2.8 with your camera's 1.6 crop factor giving a film picture angle equivalent to using a 45-120mm f2.8 zoom. But it is hard to understand why the 24-105mm is not providing good results for you. It may need to be adjusted by Canon if it has focus or off-axis problems affecting its potential for providing excellent IQ. Unfortunately many zooms come from the factory in need of adjustment to produce sharp images.
  4. You should getting used to boosting your ISO because sometimes you need the have high depth of field, f/1.4 or f/2.0 just can't give you enough of dof.
  5. I can second what Bruce says about the Tamaron 28-75 f 2.8, it is really great witth a 1.6x crop body for general use indoor/outdoor people shots and also is a super sharp lens, colours tend to be a tad warmer than comparative Canon lenses. Although not a true Macro it can also do some very nice close ups.

    That said, primes are generally better than zooms, and L primes ae about as good as they get. The 16-35 L is an excellent lens and the 35 f1.4 is brilliant.
  6. The Canon 100mm 2.8 Macro is a fine lens and very sharp at large apertures. However is does drop off in sharpness quite noticeably after f11.

    So my answer to the above is : generally yes but not always.

    Prime lenses are optically simpler and usually have fewer glass elements and mechanical bits. So they tend to work better though that is not always the case. So get to know your lenses.
  7. It all depends on which lenses you are comparing. It would be a good idea to check out test reports for the specific lenses
    you are interested in.

  8. Comparision EF 24-105mm L vs EF 50mm f/1.4
    Comparision EF 24-105mm L vs EF 35mm f/2
    As you can see, at the same apertures the primes win hands down every time (even when the zoom is stopped down). Only in corner sharpness the EF 35mm f/2 is pretty poor compared to the zoom and needs to be stopped down a lot to beat the L glass.
  9. the f stop also makes a difference, a 50 mm f/1.4 is a darn good lens, soft wide open but gets great by f/2, well at least my lens does, but usually at the same f/stop a good prime is slightly sharper, not necessarily better as better is subjective and one has to look at contrast, color, etc. the for very good low light lens wide open you have to look at the Lens, my 24L is excellent at at 1.4 and awesome at 5.6, ditto for my 135L, the 85 f/1.8 is sharp at 1.8, but you did not mention that one (considered by many the best non L portrait lens)
  10. Rent some lenses and see for yourself, if you have never used a good fast prime then I guarantee you will love it. Especially at this time of year when one is often inside and/or in disappearing light conditions. They are also usually smaller and lighter (not always 35mm L is a monster), I often carry a normal prime in my pocket with a 35mm on the camera so no need for a bag. Watch out it can get expensive for a set of L primes but there are many great non-L primes.
  11. I have the 24-105 as well as the 50 1.4 and the 100mm macro. All very different lenses so its hard to compare. I don't
    think sharpness is really the issue, all are sharp. The 24-105 is almost like a hyperzoom but with very good quality but
    yes I agree F4 has its limits and you most always need light to make this lens effective. With primes its the ability to
    shoot with a wide open aperture and also the smaller size really makes them fun to use ( the 100mm macro is not that
    small and only 2.8 so i really dont think of it as a prime )

    For me I would not bother with L primes because it defeats one of the main purposes ( at least my purposes ) You can
    get really good quality with any of the USM primes ( 28 1.8, 50 1.4, 85 1.8, 100 2.0 ) I even liked the 20 2.8.

    Everyone who has a SLR should own at least 1 prime lens. Most all of my favorite shots where done with a prime.
  12. I agree with G Dan. Check out the interactive charts at They might give you your easiest comparisons.

    But in general, yes, of course primes are sharper than zooms. That said, most of my lenses are zooms, because I find them the most versatile.
  13. Those who have thought that certain wide angle primes might out-perform their Canon wide zooms often find that certain primes do not significantly outperform the zooms.
    In general, normal to telephoto performance is often a bit better wide open with the primes.
    Beyond asking "are primes better than zooms?" it is also very important to ask "Will the prime outperform the zoom in my photography?" The answer could be yes if, for example, you work with a tripod to maximize camera stability, you always are very careful with focus, you often work with the largest available apertures, and you print large.
    The answer could be no if, for example, you are not taking maximum advantage of your lens by using tripod and so forth, you tend to shoot a smaller apertures (where the prime lens performance in not necessarily better in a significant way), or you don't print large enough that these issues become critical.
    And "better" also includes not IQ issues like the flexibility of the lens for the type of shooting you do (e.g. - is it "better" for me to be able to adapt to different focal length requirements quickly by means of a zoom, or do I have plenty of time to switch from one lens to another).
  14. zml


    The Canon 100mm 2.8 Macro is a fine lens and very sharp at large apertures. However is does drop off in sharpness quite noticeably after f11.
    And a zoom lens will not drop off in sharpness "after f/11"..? Well, diffraction is a fact of life in all lenses (L or no L) but in real life, outside the pixel-peeping world the benefits if the increased DOF outweight any loss of sharpness due to diffraction. Then, of course, there is post processing...
  15. Thanks everyone. I will probably get the Canon 100mm f/2.8 Macro for my detail and/or macro shots and continue with my Canon 24-105mm f/4 lens. I may pick up another prime like the 35mm 1.4 for some low light shooting scenarios. Right now, the majority of my shots are in the afternoon with good natural light.
  16. Rent a 24-70 2.8 and try it. It's faster than the 24-105 and on my One series bodies I have less mis-focus with the 24-70 than the 24-105. Depending upon what you're shooting, you may not want the razor thin dof that happens when you shoot less than 2.8. If you plan to shoot events, wedding receptions, etc in low light, it's unlikely that you'll want an aperture greater than the 2.8 aperture, which, of course, is the largest aperture available in Canon lenses.
  17. Comparing the 70-200 f/4 IS with the 100 macro, there is hardly a difference in image quality:

    Prime lenses do not generally offer higher image quality, it all depends on which lenses you compare.
  18. "Well, diffraction is a fact of life in all lenses (L or no L) but in real life, outside the pixel-peeping world the benefits if the
    increased DOF outweight any loss of sharpness due to diffraction. Then, of course, there is post processing..."

    Not if you make very large prints of highly detailed subjects and you shoot with a crop sensor camera. And post processing
    won't help much here.
  19. my 17-55 2.8 is sharper than my 35L and just as sharp as my 135L
  20. I have all of the lenses you metioned with the exception of the 50 f1.4. The Canon 100 f2.8 macro is a wonderful lens for macro and a general purpose prime, but as other have noted it is not a small nor a particurly fast lens. In general use, I don't notice a lot of difference between it and the 24-105 L, as other factors are typically more important than the minor sharpness advantage it has over the zoom. If you don't intend to do macro, the Canon 85 f1.8 or 100 f2 would be better chocies for their speed, size and cost advantage.

    The 35 f2 is very sharp in the center but falls off a bit at the edges. Contrast is lower at f2, but at f2.8 or 4 it will beat the zoom but not by a huge margin. It's main drawback is it is an old design, with a buzzy micromotor. I have always suspected but never proved that the micromotors in my 35 f2 and 50 f2.5 macro are a little less accurate than USM motors.

    If Canon updated the 35 f2 with USM, kept the same optical design and the price to under $350, I suspect they would sell them by the truckload.

    Sadly, I think that apart from kit lenses Canon has not introduced a lens for under $450 in years.
  21. Prime lenses frequently offer substantially larger apertures in a reasonably priced, smaller package.

    About the fastest zoom you can get is f2.8, one stop better than your f4 lens.

    F1.4 to f1.8 or f2 primes are often not unreasonably priced. Give them a try. At the focal lengths you are talking about, you really don't have to spend a lot to experiment, and can likely sell off and recoup much of your cost if you don't like the primes. I often recommend renting before buying, but in this case I'd almost be tempted to say that renting might be a waste of money with a $300-400 US lens that resells used for $275-350, like the 28/1.8 or 85/1.8. On the other hand, if looking at a more expensive premium lens like the 35/1.4, renting first for a couple days might be a good idea.

    In the good/bad old days, primes were the only way to go and zoom image quality was almost universally poor. Today, on the other hand even lower entry level to mid-grade zooms are surprisingly close to primes in image quality, and some of the best zooms are hard to tell apart from primes.

    I think the biggest reason to experiment with primes is that you'll find you actually shoot differently with them. With primes I'm less lazy, more inclined to move around and look for different angles to shoot, and put more thought into lens changes.

    There are times and places where zooms are essential, that's why I have several. There are other times and places where primes work better for me, which is why the majority of my lens kit is primes.
  22. Has anyone else compared a particular model of prime versus an L zoom? I would be curious of the results of the cheaper primes.

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