WoMP: Zooms

We got a lot of requests in the comments to talk about lenses, so here’s our first forray into that realm.  What kind of stuff do we look at when it comes to lenses?  And how do the manufacturer brands (Nikon & Canon) stack up against the cheaper 3rd party lenses?

Clarity & Sharpness:  The first half of this is done at 1080 resolution, but scaled down from a high-res still.  So it doesn’t matter what camera you are shooting on, if you’re delivering 1080, that’s as good as it will get.  We see that while the sharpness difference is visible, it’s not huge and really the limiting factor is the pixelation from the low res.

When we look at the 21 megapixels (from a 5D mkII) the variations in lens sharpness and contrast are more apparent.  In the center of the frame we can’t really see a sharpness difference, but there is a bit of a difference in contrast.  Toward the edges of the frame we see some pretty brutal chromatic aberration (the colored edges on the high contrast areas).  Chromatic aberration is pretty “fixable” in post.  It’s a predictable mis-alignment of the color channels toward the edge of the frame.  If you shoot raw and edit in Lightroom, as I do, I pay less attention to that.  Nonetheless, the Canon looks the best on the wide end, and the Nikon looks the best on the tight end (in my opinion).

One other note:  I actually had to reshoot this test because the first time I did it I forgot the Vibration Compensation switch ‘on’ for the Tamron.  Since I was shooting with slow shutters on a tripod, it actually blurred the image.  So while the VC is a really solid feature that you would want to use a lot, it’s definitely just an ‘as needed’ thing.  You can’t just flip it on and forget about it.  It’s good to have the option, but you have to remember to be aware of it.

Is the Bokeh OK?

Get it?  The title rhymes.  :)

The one wrench in this mix is the Nikon seems to have a close-focus distance that is sliiiiiightly closer than the others.  So when I slam the focus all the way to the foreground, it’s actually defocusing the background a bit more.  Keep in mind that the size of the out-of-focus area is a consequence of aperture and focus distance.  That has nothing to do with the bokeh, which refers to theshape and quality of that out-of-focus circle of confusion.

The bottom line here is that I think the lenses were very similar, and you really should not be letting this affect your decision too much.  There aremuch more important things to worry about.

Vignetting & Brightness:

These were all shot at the wide-end of the zoom.  The wall behind me was evenly lit.  Holy crap that’s a lot of vignetting across the board, and the Sigma is outrageous.  But once again go back and look at that last forest shot.  That was wide-open just like this, with the corners going crazy dark.  You didn’t notice it then, did you?

Optical Stabilization

This is the real trick of the Tamron.  It’s something that Nikon and Canon have implemented in their other (cheaper) lenses, so why not in these!?  It’s souseful.  For video it means you can usually handhold a DSLR and get some nice shots, which is impossible otherwise (just don’t try riding on the hood of a car, that might be too much for it).  And for stills it allows amazing flexibility.  Tripods are for suckers.  I love this stuff.


“But Kevin” you say, “what about the build quality focus speed accuracy weather sealing flare resale value and sexiness!?”  To which I respond:  I think I focused on the most curious stuff.  The focus speed is excellent on all of them.  The build quality seemed solid and I can’t really test that without dropping 20 of each lens on the ground.  Ditto weather sealing.  Resale value is too much speculation.  And sexiness, well I just can’t help you if you’re trying to prove something with your lens brand.

Then you say, “But Kevin, the Nikon and Canon were clearly sharper, how can you choose a winner that gives you soft photographs?”  To which I reply:  I did struggle with that.  But it came down to the following.  I have never once seen a great photograph and thought “man this would be amazing if only the very corner of the frame was a tiiiiny bit sharper.”  Many many times I’ve busted a video for being too shaky, or tried to get a still shot in low light handheld and not quite pulled it off.

If I honestly think back through my shooting over the past few years, and which shots didn’t quite come off, and which ones did, this is where I end up.  Good Vibration Reduction gives me more better shots than edge sharpness.  I spend far longer blurring and vignetting the far reaches of my photographs than I do sharpening them.

Basically I think that if you shoot mostly video, it’s a no-brainer.  The Tamron is king.  If you shoot photojournalist stuff, ditto, no brainer.  Get the shot and stop worrying about someone pixel-peeping the corner of your frame.  If you do studio/advertising that sort of thing, then maybe the camera brand lenses will serve you better.  But if you’re really so worried about that extra sharpness, throw a prime lens on there instead.  I don’t think that’s what these zooms are about.  They’re about getting the shot; the Tamron is the one that can get the shot.

And before I sign off, I kinda @#$% on the Sigma.  But keep in mind it costs about one third what the Canon does.  That is not one third the performance!  It is way better!  Particularly for video, if you’re tight on money or feel it would be better spent elsewhere, I think the Sigma is a fine choice.  The Sigma and a plane ticket will give you well-better pictures than any of the other lenses.  A used Sigma would be a great foray into this realm, and would be preposterously cheaper than any of the other options, for a minimal quality hit.