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07-06-2011, 02:12 PM   #1
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Mirror lens vs teleconverter better?

I have a K200d which I brought with me to Yellowstone recently, and found myself wanting more range (on the tele end- the animals are always further than you want, eh?) than I had with my Tamron 28-200 (opted for that which I got with a ZX-L rather than the kit 18-55 and 55-200 that I got with my K200d).

I can't justify splurging on something like a Bigma 50-500, so exploring my options. Mirror lens 500mm or a teleconverter seemed like the best options. The fixed length mirror lens would seem to limit your framing options, but maybe better image quality? I think the speed of most mirrors (f8 or slower) would probably be about equivalent to a zoom tele + TC, no?

I'm leaning towards getting a 2x teleconverter- less mass to carry around (rather than carrying my 28-200 AND mirror 500, the 28-200 with the TC would get me almost 400mm effective) at the loss of some image quality? Probably the biggest prints I would ever do are 8x11 so I'm not going to ask for razor sharpness. Maybe most challenging subject encountered at Yellowstone- hawk in flight- not sure you can tripod that flying overhead, and the long lens will really amplify hand held shake- so maybe that just can't be done without a fixed focal howitzer of a lens since you would need both speed and length. If that's a lost cause, then I'll want whatever's best for the range of the rest of the time. Something to take on 3-8 mile roundtrip hikes, taking the range of stuff- mountain vistas, grizzlies at 100+ yards etc.

07-06-2011, 02:33 PM   #2
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The 28-200mm is f/5.6 at the long end. With a 2x teleconverter that's f/11 which will make it very hard for the autofocus to work.

Mirror lenses are bulky rather than heavy, and I think they're all manual focus. You're aware of the doughnut shaped out-of-focus highlights from a mirror lens?
07-06-2011, 02:34 PM   #3
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The TC's I've used reduce IQ too much. But that could be the luck of the draw. Some TC's have good reputations; see the lens database reviews. TC's are pretty lightweight, in the 150-250g range. But I really like my Sakar 500/8 mirror, which weighs only 420g and cost me US$13 shipped. Yeah, I got lucky. And yeah, putting a 2x TC on your Tamron 28-200/3.8-5.6 will make it f/11 at the long end, pretty slow, and still with less reach than the mirror. A matched TC on a fast long lens gives good IQ. With your Tamron, you'd probably get better IQ just by cropping the shots.

EDIT: Yes, mirrors produce doughnut bokeh. I try to shoot so as to avoid glittery backgrounds etc.
07-06-2011, 08:31 PM   #4
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It will of course depend on the specific lenses involed, but in general, I'd expect putting a TC on a basic consumer to perform a bit worse tha simoly cropping, and the mirror to perform a little better. So, by extemsion, the mirror should be more than a little better than the TC.

Note when I say rhe TC will probably be worse than cropping, than menas it will likely be a waste of both money and space.


Last edited by Marc Sabatella; 07-07-2011 at 10:24 AM.
07-07-2011, 02:51 AM   #5
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On a clear day with norminal temperatures F8 is fine, when you are trying to take photos in low light or late in day a faster F is always going to better even with F2.8 lens with 1.4x or 2x the they will better off than a f8.
If you are concerned about price then F8 will be fine, how you will get bored with the limits will offer.
07-07-2011, 03:15 AM   #6
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QuoteOriginally posted by erf Quote
Mirror lenses are bulky rather than heavy, and I think they're all manual focus. You're aware of the doughnut shaped out-of-focus highlights from a mirror lens?
My 800mm f8 is huge, but surprisingly light in weight. And the doughnut bokeh can be quite nice... If you like it.
07-07-2011, 05:05 AM - 1 Like   #7
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I've had a couple of the cheaper mirror lenses (Spiratone, Kalimar) and currently own a Russian 3M-5CA 500mm f8 mirror lens. The Russian lens positively smokes the cheap ones I've had. There's no comparison. It produces images on par with those from my Tamron 60-300 SP, which is a pretty well regarded conventional zoom. And the 3M is noticeably better than the Tamron 60-300 / Tamron 01F 2x teleconverter combo. If you do go with a mirror lens, I'd hold out for a 3M, Tamron, or Tokina. My experience with the others has been disappointing, but that 3M is sure a keeper.
07-07-2011, 05:13 AM   #8
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How does the autfocus work on the f-8 lenses? I know they aren't autofocus, but does the camera still beep and give you the little red squares to show you what's in focus, or are you completely on your own?

07-07-2011, 05:25 AM - 1 Like   #9
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QuoteOriginally posted by normhead Quote
How does the autfocus work on the f-8 lenses? I know they aren't autofocus, but does the camera still beep and give you the little red squares to show you what's in focus, or are you completely on your own?
With any manual-focus lens (MFL) you still get focus confirmation. I use CIF and focus confirmation with my 500/8 mirror, 12mm fisheye, enlarger lenses on bellows, mount-reversed lenses, whatever. With a MFL on my K20D, only spot and center-weighted metering are active, not matrix, but I can live with that. I use my 500/8 mirror primarily for street-shooting discreet 'portraits'; with CIF, focus is dead-on.
07-07-2011, 08:32 AM   #10
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A Sigma/Tamron 70-300 or Pentax 55-300 are likely to give better images than a Tamron 28-200 + TC, even when adjusted to matching resolution.

For a hawk in flight, no reason to use a tripod. In fact, for the 3+ years I've been shooting local wildlife (nothing exciting like grizzlies, though), I've never used a tripod.
07-07-2011, 10:05 AM   #11
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thanks for the advice. sounds like a tc is better than cropping only when your lens resolution is over 2x better than your camera sensor... which is almost never (maybe in the *ist 6MP days, but not now, nor when film was king).

thinking more i realized whether going with a tc or mirror i would need to do changes in the field under suboptimal conditions. tired, sweaty, dusty, and in a hurry (before that varmint scampers off) so maybe i'm better off using a (*gag*) point n shoot to handle one end of the range, the k200d the other. with that, should it be k200d+mirror for tele, p&s for wide to zoom, or go the other way, k200d w/ kit 18-55 for wide mid, and the p&s to handle the tele?

i wish i had the 55-300 as it would have been at least a bit more tele, but on the fleabay auction a year back they only had the k200d kit w/ the 18-55 and 55-200 for ~$60-80 more than w/ the 18-55 alone. my tamron 28-200 from my ZX-L covered almost all that range in one so i opted for that despite probable iq loss for a wide range zoom.
07-07-2011, 10:15 AM   #12
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btw any hints for catching flying hawks (& other birds) beyond practice practice practice? i tried panning with him but probably wobbled too much. pretty bad edge blurriness too, not sure if from the high contrast (near direct overhead with sky as backdrop).
07-07-2011, 10:35 AM   #13
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As always in action shots, the faster the shutter speed, the better. A low-light mentality helps - shoot wide open if necessary, crank up ISO as high as you need. Yes, lenses are sharper stopped down, and higher ISO means more noise, but I guarantee you're better off with either of those problems than with motion blur. Of course, I'm not saying go straight for ISO 1600 every time, but if your picture are blurry, then by definition, you need a faster shutter speed, and those are the only two ways to get there.

The difference, BTW, between 200mm and 300mm is significant, but not so much that cropping an image from the 50-200mm at 200mm is going to be *that* much worse than an image from the 55-300mm at 300mm, especially viewed at web resolution. My 50-200 actually performs slightly *better* at 200mm and cropped than my Tamron-made Quantaray 70-300 does at 300mm. But the 55-300 is better than the Tamron, and I have no trouble believing it is better than the 50-200 cropped, since it's a better lens overall.

BTW, for BIF, I find a manual focus lens easier than dealing with an AFlens. The focus motion is much smoother with most MF lenses. The M200/4 works quite well. It is also the only lens I own that actually can produce ever so slightly better results with my Keno 1.5X TC than by simply cropping (only at one specific aperture, but it's a good aperture for this kind of thing). So my M200/4 + 1.5TC is a viable combo for BIF, in good light anyhow. In less good light (and by that, I mean anything but a bright sunny day), I'm still better off without the TC.
07-07-2011, 10:37 AM   #14
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QuoteOriginally posted by Marc Sabatella Quote
It will of course depend on the specific lenses involed, but in general, I'd expect putting a TC on a basic consumer to perform a bit worse tha simoly cropping, and the mirror to perform a little better. So, by extemsion, the mirror should be more than a little better than the TC.

Note when I say rhe TC will probably be worse than cropping, than menas it will likely be a waste of both money and space.
+1. TCs are meant for fast lenses, not for consumer zooms. Use a longer consumer zoom or a mirror. If you are going to get a mirror, ignore the Samyang 500/8 version and go for the Samyang 500/6.3 - it is a bit more expensive but it seems to have better IQ. If you want a better consumer zoom, get the DA 55-300 or the silver FA 100-300/4.7-5.8.
07-07-2011, 10:45 AM   #15
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QuoteOriginally posted by donyjunk Quote
btw any hints for catching flying hawks (& other birds) beyond practice practice practice? i tried panning with him but probably wobbled too much. pretty bad edge blurriness too, not sure if from the high contrast (near direct overhead with sky as backdrop).
If you are panning, turn off SR. The panning motion of the camera confuses the SR, resulting in blur.

As Marc points out, you need to keep the shutter speed up. Sometimes you can get lucky and if the bird is flying in a predictably parallel plane to you, you might be able to get away with a slow-ish (1/100s) shutter, but I usually try to get close to 1/1000s.

My experience with Tamron 70-300 lens is different than Marc's. Perhaps the Quantaray versions have lesser QC? I found 300mm on the Tammy to be as sharp as the Pentax 50-200 @ 200mm.

Last edited by luftfluss; 06-08-2016 at 08:25 AM.
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