Friday, January 18, 2008

Inexpensive Super Telephotos

Unidentified backyard bird
Canon 70-200mm f/4 USM

You may think that "Inexpensive Super Telephoto" is an oxymoron. And you'd be right, at least if you want good images from it.

If you are seriously interested in birds or sports where you can't get close to the action, you'll need a super telephoto with focal length 400mm or longer. And suddenly, while you have tons of choices at shorter focal lengths, the choices out there get very few and, for the most part, very expensive.

I've already talked about mirror lenses, and my Sigma 600mm F/8 is on its way to me as I write this. I've also ordered the FD-to-EOS converter, so hopefully I'll get some sample images up by the weekend. Hopefully...

This time around, I want to discuss some of my research into inexpensive refractive lenses which give good quality results (i.e. not a $150 70-300mm Phoenix/Tamron/Sigma/generic lens). Granted, those entry level zooms have their place, but the main trade off of the cheap lenses is the long end, so if you are interested in shooting sports or birds outdoors, they aren't going to cut it. My Tamron 70-300mm f/4-5.6, while pretty short at the wide end, got unbearably soft above 200mm. In fact, I'd be better off upsampling from a quality 200mm than using the 300mm range of the Tamron (see full review). While newer or more expensive zooms (especially the Canon 70-300mm f/4-5.6 IS USM, $550 at Amazon) are improved in this range, the long end is usually where performance begins to decay, especially wide open.

Besides, if you need 300mm (which really is a 480mm equivalent for APS sensor dSLRs) you can always use a high quality 200mm zoom, like the Canon 70-200mm f/4L USM (review, $550 at Amazon). For the record, if you want to shoot anything indoors at 300+mm, good luck, you're going to have to just suck it up and spend on fast, heavy glass.


An Example...

Why is it really necessary to go beyond 200mm anyway? Well, let me illustrate with an example from birding.

I shot a sequence of images of the bird in the composite that began this post. It was shot on a Canon 20D with Canon 70-200mm f/4L USM @ 200mm, approx 1/2000sec, ISO 200. I'll explain the boxes and notations in a second.

Pretty decent shot, I didn't nail the focus but was pretty close, as you can see from the 100% crop below (click it to see it at full size, FYI).

The nice thing about the 70-200 L-glass is it really comes close to the theoretical limit of the sensor, especially if you convert from RAW like I did. Every pixel counts. The image could be posted with some minor processing at web-resolution and I'll be proud of it. But beyond web resolution (approx 75 dpi) it falls short, especially if you have have to use an ISO greater than 200 (some of the images were shot with ISO 400 and the noise was distracting and hard to remove). And a smaller bird, like a hummingbird, is very difficult to get (trust me, I've tried).

So, what will longer focal lengths give us? Refer back to the original image and note the green (400mm) and red (600mm) boxes. These are the areas that would be covered by the respective lenses. Crops of those areas, for examples, are below (not full-res though):


Essentially, if I crop from a 200mm, 8 megapixel shot to get the same magnification as a 400mm lens I'm only getting a 2 megapixel image. 2 megpix images are ok for printing as long as they are perfect technically (no problems with blurring, focus, etc). If I crop to a 600mm equivalent, I'm left with less than a megapixel (think cellphone camera). Obviously, if you care about using your images for anything but the web, either now or in the future, 200mm isn't going to cut it for taking pictures of birds smaller than chickens.

The other advantage of longer glass, which you'll know about if you've ever tried to take pictures of birds, is you can use a much longer working distance to get the same shot of a bird.


Let's Talk About Glass...

So, when I began, I took a survey of what refractive lenses are out there in the sub-$1000 range (for new lenses, I relaxed that a bit). You can get some pretty good quality for the price, but you mostly give up your maximum aperture, typically settling for f/5.6. Obviously, I don't own any of these lenses, so my brief comments are gleaned from looking at a ton of reviews online. Since I shoot Canon, this survey is Canon-centric, specifically EOS, although the third party lenses fit a lot of cameras (and are often cheaper than the Canon mounts). Also, I quote Amazon's price for the new lens for comparison, but look around before you make any big purchase. Finally, the LP[X/Y.Y] is the Lensplay rating, click the link to see the page.

Let's start with the fixed focal length primes:
  • Canon 400mm f/5.6L USM ($1,080 at Amazon) LP[9/9.4] Top notch lens, expensive, but popular with bird photographers. This is the lens I'd get if I had the cash. None of these lenses have been listed on eBay in the last month -- that's the sign of a good lens. (Luminous-Landscape review comparing it to Canon 100-400mm F/4.5-5.6L)
Yeah, that's it. Nobody makes long primes anymore that aren't really fast (and expensive) because the general consumer would rather have a zoom. Which kinds of screws us, the cheap but knowledgeable photographer who'd rather have the better quality of a prime at a cheaper price.

Well, how about the zooms:
  • Canon 100-400mm f/4.5-5.6L IS USM ($1,300 from Amazon) LP[8/9.0] Highly respected, includes optical image stabilization, highest price tag of any lenses on this list. I put it on here mostly for completeness. At the long end, wide open, sharpness isn't perfect (according to the Luminous-Landscape review). The Nikon equivalent is the 80-400mm.
  • Sigma 50-500mm f/4-6.3 EX DG HSM ($920 at Amazon) LP[6/9.0] a.k.a. 'Bigma' since it is a 4 lb (2 kg) monster. The only known lens with a 10x zoom range and a 500mm long end. Well regarded, especially by birders. Includes HSM (like Canon's USM) but has a larger price tag than most of the other zooms.
  • Sigma 80-400mm f/4.5-5.6 EX OS APO ($1,000 at Amazon) LP[7/8.5] Sigma's direct competitor to the Canon 100-400mm IS, since OS is Sigma's optical stabilization designation. Generally well-reviewed, but whether it is better than the Canon 100-400mm is up for debate (probably not).
  • Sigma 135-400mm f/4.5-5.6 EX DG APO Aspherical ($525 at Amazon) LP[6/7.7] This seems to be the budget super-zoom in the Sigma line, but I'd generally avoid it in favor of the 170-500mm below. Even thought it is cheaper than most lenses, the 400mm end is supposed to be quite soft.
  • Sigma 170-500mm f/5-6.3 DG RF APO Aspherical ($710 on Amazon) LP[6/7.7] This lens was actually news to me when I wrote up this post, but Amazon reviews seem to be quite positive (click link above). Photographyreview thread with sample pics and photographyreview lens page. Both those links talk about softness wide open and difficulty with autofocus with the f/6.3 aperture. Generally reviews are pretty mixed with a slant towards positive.
  • Tamron SP Autofocus 200-500mm f/5-6.3 Di LD IF ($830 on Amazon) LP[7/8.4] The reviews I've been reading say this lens is good, but it is soft on the wide end after 400mm. Bob Atkins has an excellent review with lots of images at photo.net.
  • Tokina AF 80-400mm f/4.5-5.6 AT-X Pro D ($650 at Amazon) LP[5/6] (may be old version?) Mixed reviews at photographyreview.com, but again, that may be an older version. General consensus is that it is a bit soft on the long end.
If you've already got a good quality lens in the <=200mm range and our looking for great quality at the long end, zooms generally aren't the way to go. Most, if not all, zooms give up sharpness at the long end which is usually your biggest concern if you are wanting to shoot birds. Yes, even the Canon 100-400mm. So don't expect perfect sharpness wide open at the long end. Another big factor is image stabilization. I've never used IS/OS so I can't testify if it is worth the increased premium it adds to the lens price. I expect it'd be very useful if you like to handhold your camera at the long end, so it might be something to keep in mind. Currently only the Canon 100-400 and Sigma 80-400 include it. Another thing to note is the sheer number of lenses in Sigma's range. I'm shocked they don't reduce the number of zooms by cutting one or two out (I expect they will soon). The 50-500mm is super heavy but great if you want a crazy long zoom. The image quality is supposed to be quite good and the price reflects that. My personal opinion would be either the Sigma 50-500mm, Sigma 170-500mm or Tamron 200-500mm if you are interested in birding. The extra length allows you to compensate for the decreased performance at the long end. Ultimately, I'm not planning on buying a new zoom, so I haven't done a detailed comparison of these three lenses. Expect to spend a decent chunk of change no matter what zoom you choose, and for the price, do whatever you can to try out the lenses before purchasing. Being the cheap guy I am, I think the used market has some better deals...

The Used Market

  • Tamron AF 200-400mm f/5.6 LD IF LP[6/7.7] [eBay prices from $200 to $300] I had a real hard time finding reviews on this lens on the web. It has been replaced by the Tammy 200-500mm. I'd generally steer clear of this lens since reviews point to it being soft at 400mm wide open. The good news is there are plenty floating around on the used market for all camera mounts.
    • Photo.net thread mentioning it is a bit soft on the long end and recommending the Sigma 400mm instead.
    • Momentcorp.com review which actually includes example 100% crops. You can definitely see the softness on the long end, so if you are interested in bird or sports photography, the soft long end will probably bother you a lot.
  • Tokina 400mm f/5.6 AT-X SD LP[not posted] [eBay prices from $200 to $300] This is an older lens, and seems to lack some of the special coatings/lens materials of the newer lenses, which causes more CA. I'd be happy to own it though. Update 12/31/08: An eBay seller reported that they do not suffer from the Error 99 problem. That one sold for $250 including shipping.
  • Sigma 400mm f/5.6 APO HSM LP[7/8.3] [eBay prices from $350 to $500] This is my top choice for a used lens, if I had the money. All reviews are very positive and there are a decent number out on the used market. Update 1/2/09: Turns out there's four versions of this lens out there (details) -- non-APO (not recommended, maybe $150 used?), APO but non-HSM (smaller focus wheel, ~$200-$250 used), APO telemacro, but no HSM ($250-$300 used, monster focus wheel, filter size 72mm), and HSM (filter size 77mm). The HSM is the newest and the best, but the APO telemacro is pretty good too. All suffer from the Sigma Err99 problem on 10D?, 20D+, 5D+ Canon cameras though, so assume that you won't be able to use apertures other that wide open reliably unless the lens has been rechipped. FYI, Sigma no longer rechips these lenses.
For me, it ultimately comes down to choosing between the Sigma and Tokina because I'd prefer the increased sharpness of a prime. A direct comparison of the two can be found at this Dyxum page comparing the Sigma and Tokina 400mms. Even though the sample images seem to show the Tokina as a bit sharper, the author prefers the Sigma for real-life use. The Sigma definitely has more chromatic aberration than the Tokina.

Especially notable is the difference in price -- if you can get a Tokina 400mm for $200, that's a great deal and worth purchasing, even if it isn't quite as good as the Sigma. So, if you are patient, the best budget birding lens is probably the Tokina 400mm. Overall, you can cut the cost in half or less if you are willing to go with a used prime vs a new zoom.

Hopefully this compilation of cheap super telephoto options will be helpful to you. I know I'll be able to use it as a resource once I can finally scrape together enough cash for a good birding lens.

Oh, and my Sigma arrived yesterday, although I'm still waiting on the converter to mount it to my 20D. More details to come.


Random References:

Search on eBay:

For convenience, here's an eBay gadget listing the current sales of 400mm budget f/5.6 lenses. Always double-check the listing to make sure they aren't the FD versions (there's a bunch floating around). I was careful with the search terms, so there should be only a few good matches listed at any one time.



3 comments:

Ashley Pomeroy said...

I'm not sure if it was an option back in 2008, but I've always wondered if if would be more cost-effective to buy a decent 200mm lens and a used Micro Four-Thirds or Four-Thirds camera, as a kind of "free" 2x teleconverter. The old E-500 is now about half the price on the used market as a new Canon 2x extender.

The thought of a tiny E-P1 mounted on the back of a telephoto lens appeals to me, although I suspect it would be impossible to hand-hold (you'd have to see the screen to focus). You could use almost any lens ever made, though.

Ashley Pomeroy said...

And, er, you had the exact same idea two years ago:
http://stanfordphoto.blogspot.com/2008/03/sigma-600mm-f8-reflex-performance.html

That'll teach me to not search the archives.

Sean said...

Hey Ashley,

Thanks for the comment.

While you mentioned my previous post, you do have an excellent point about the use of older digital cameras with smaller chips to get more length out of mid-range telephotos.

In the article you referenced, I found that the 600mm Sigma really had its flaws exposed by a high-density sensor. I think that certain other lenses (such as 200mm primes) might have a better shot at holding up to an older crop sensor. For instance, the E-500 is an 8MP sensor -- you might get decent images out of a 200mm prime with an 8MP sensor.

Newer, 12 MP sensors would probably go well beyond the resolving power of the lenses, sadly. There was really no point when those older manual focuses lenses were made to go beyond the resolving power of 35mm film (around 10-20 MP full frame).

It is an interesting idea though, and if you try it, I'd be curious to hear the results.