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09-05-2010, 06:12 AM   #1
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TC +200mm or 500mm mirror

I was thinking about getting a long lens (like 400mm Tokina etc), but in the absence of reasonably priced long lenses, I have started considering a 500mm mirror lens or using a TC with my M 200mm.

What are people's opinions on the relative merits of using either a mirror lens, or a dedicated Pentax 2x TC with a M 200mm? I think the M 200mm combo will give a brighter viewfinder (note this is for film, so I have a brighter viewfinder than a DSLR) and more depth of field control. But I am wondering which will give the better IQ. It seems the Tamron SP 500mm is readily available on Ebay for about GBP 80, with filters and tripod mount and box, whereas the Pentax T6-2x costs about GBP 50. I'll be using a tripod, so really, f4 speed is not important to me, rather greater depth of field stopping down to f11.

09-05-2010, 07:36 AM   #2
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Check out the mirror lens club:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/71775-mirror-lens-club.html

Note the donut shapes in the out-of-focus areas. Some people like the look, some don't. If you don't, then the M 200 with a teleconverter would be the better option. Or a 2nd hand A or M 400/5.6.

A 2x converter on the M 200/4 makes it a 400mm f/8 lens, quite dark and hard to focus. Hence my suggestion that you perhaps look for a 400mm lens.
09-05-2010, 07:50 AM   #3
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QuoteOriginally posted by hoojammyflip Quote
I was thinking about getting a long lens (like 400mm Tokina etc), but in the absence of reasonably priced long lenses, I have started considering a 500mm mirror lens or using a TC with my M 200mm.

What are people's opinions on the relative merits of using either a mirror lens, or a dedicated Pentax 2x TC with a M 200mm? I think the M 200mm combo will give a brighter viewfinder (note this is for film, so I have a brighter viewfinder than a DSLR) and more depth of field control. But I am wondering which will give the better IQ. It seems the Tamron SP 500mm is readily available on Ebay for about GBP 80, with filters and tripod mount and box, whereas the Pentax T6-2x costs about GBP 50. I'll be using a tripod, so really, f4 speed is not important to me, rather greater depth of field stopping down to f11.
The Tamron is a nice lens but it's a fixed (at f8) aperture plus you need the proper adaptall mount for it. To change exposure as you would with aperture (DOF aside), you need to use the rear mount ND filters that come with that kit (so make sure they are there). Doubling the M200 isn't a bad way to go but I've yet to find a TC that did a great job of it. No experience with the Pentax TC's however.

09-05-2010, 10:26 AM   #4
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another way to go long

I've only taken a couple of test shots, but the 55-300 and a good 1.5x seem to work well in good light - that gets me to 450mm. I really don't shoot that way often, so cannot justify a separate lens.. nice to know I can do it though!

09-05-2010, 10:51 AM   #5
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The IQ of my Samyang 500mm mirror is is borderline acceptable if I do everything right. Adding a 2x TC to this lens would likely result in even poorer quality photos. I have seen these combinations sold on Ebay. I would recommend saving up a little longer for a better MF lens like a Takumar or M. They won't break the bank and the results will be much better. I have used a 2x converter with a 200/4 Tak with good results.
09-05-2010, 11:17 AM   #6
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I'm pretty sure I will just go the route of the TC+M 200mm rather than the mirror lens due to the doughnut bokeh of a mirror lens which I had not really considered. Looking around, the mirror rings OOF effect doesn't wait for highlights, it will do it on anything. I'd not add a 2x to a f8 lens...at f16 you would be lucky to see through the viewfinder. Ultimately, the M 400mm might have to come via an international search on Ebay as I have not seen one go in the UK.
09-05-2010, 11:49 AM   #7
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QuoteOriginally posted by hoojammyflip Quote
I was thinking about getting a long lens (like 400mm Tokina etc), but in the absence of reasonably priced long lenses, I have started considering a 500mm mirror lens or using a TC with my M 200mm.
I once bought a mirror lens(a few years back) and hated it so much I ended-up using it as a prop device for my flex lamp - not very sharp, CA and incredibly annoying OOF effects(doughnut shapes).

Having said that, I don't think an M 200mm with TC will make a good candidate either given the already present level of CA with that lens, adding a TC will only accentuate this further, making it very difficult to get good shots out of imo.

The best current possible scenario I've come across(myself) on a budget tele. was coupling an SCM AF 1.7X TC with a Tamron 60-300. The TC can be quite expensive, BUT... it does change a manual focus lenses into an auto focusing one and so the TC is quite versatile in terms of use, not to mention that it's the sharpest TC I have ever used(rivaling 1.4x).



The Tamron SP 60-300 is a very affordable lens which can be had on eBay anywhere between 60-130USD. However... getting good 510mm IQ out of it will require a fair bit of TLC as the lens was never conceived for such focal lengths to begin with. Having said that, it is an adaptall lens, and so shooting with a TC would pretty much require that you attach the PK/A adapter to it(which can be rather pricy). Otherwise, you'll be shooting stopped down and the TC AF simply won't cope with anything over F4(on a good day ). However... attach a PK/A adapter and the TC is good as gold(AF away).

The first issue is the lens has no tripod mount, therefore, if you factor in overhang and the effect of micro vibrations present at 500mm+ then a mount will be essential. The good news is that you can buy a $6 mount on eBay and attach it to the lens as seen here:



The second issue is that 85% of the SP 60-300's out there don't come with a lens hood. And since the original lens wasn't conceived to extend to 500mm, a good hood system will be critical in maintaining a good contrast. My advice on this would be to grab a 62-82 step-up ring and attach a low length tube(hood) coupled with a deep flower or petal hood. Something along the lines of this:

.

All in all, I've had great success with this setup while saving for an FA 300mm prime.

PS. I took some 510mm resolution chart test shots at some point with this combo which beat my old Bigma on the long end. let me know if you're interested and I'll dig them-up for you.
09-05-2010, 12:39 PM   #8
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Thanks for the tip though, I actually saw one of the SP 60-300 lenses going on ebay for GBP 15, or USD 25 and another at about USD 50, so they are cheap in the UK.

Maybe I have been lucky with my M 200mm, but I see less CA than with other lenses, like the Viv S1 70-210mm by Tokina, the f3.5 200mm from Komine or the M 80-200mm v1.

I have heard rumours that the Sigma lenses develop lens separation, so I would be happier sticking with a Tokina, although their colour seems cool to me, having had the v2 Vivitar S1 70-210mm.

09-05-2010, 01:28 PM   #9
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QuoteOriginally posted by hoojammyflip Quote
Maybe I have been lucky with my M 200mm, but I see less CA than with other lenses, like the Viv S1 70-210mm by Tokina, the f3.5 200mm from Komine or the M 80-200mm v1.

I have heard rumours that the Sigma lenses develop lens separation, so I would be happier sticking with a Tokina, although their colour seems cool to me, having had the v2 Vivitar S1 70-210mm.
That is interesting on the M 200mm, I had a few copies over the years and gave-up on them. Maybe there are variances between them, or.. it might of been my shooting style too. But I found them to be very CA prone especially PF in highlights. But it was once a TC was installed that it really seemed to become a problem.

On the issue of the Vivitar 70-210, I do have a a v3 Komine around, which I used to use for macro, but I've since hung-it-up to dry in favor of a 90mm Tamron. Having said that, I never really compared it to anything else on the long end so I can't really comment on that.

There is one lens that's been on my 17x TC however, and that's the infamous DA 50-300. I've seen a few light samples on the forums with this lens, but nothing concrete in terms of resolution testing. Though I'd be very curious to see how it holds-up against the 60-300 Tamron.
09-05-2010, 01:43 PM   #10
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Indeed, I was very pleasantly surprised at the performance of this lens. I recently shot a test shoot for my M lenses (I've got 7 I think) to get the same object size, so 20x focal length for the object distance on a high contrast scene (white candle on black fence background, 4m away, in my garden). Here is the 200mm M wide open:



and here is the M 85mm wide open


beauty is in the eye of the beholder as they say, but I have a feeling that the M 200mm is under appreciated. Its wide open performance knocks spots off the 85mm for CA. Bokeh may be another matter entirely, and for portraits the M 85mm is no doubt better, but as a tele lens, the M 200mm is not too shabby.

To be honest, I'd be surprised to hear a zoom on a TC outperformed a tele on a dedicated TC, I've just read the Pentax T6-2x guide and it sounds like it was designed for the M 135 to M 300 range of lenses. There is only one way to tell, and thats to purchase it. At the end of the day, I don't think I could put up with the donut bokeh of the mirror lenses as pointed out by Ole, and the M 400mm is as rare as hens teeth, so the M 200 or K 300 on a TC is my likely option.
09-05-2010, 01:59 PM   #11
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If you are only getting a TC it is a toss up

The 200 f4 plus 2x will give you 400 F8 against the mirror at 500 f8

I would call it a draw. Slight increase in magnification against slightly more sharpness and aperture control

Now if you had the 1.7x AF TC and a 300F4 then the lens and TC would win hands down. Look through my past posts for examples using this combo. Faster than a
Mirror and much much sharper
09-05-2010, 02:03 PM   #12
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QuoteOriginally posted by hoojammyflip Quote
Here is the 200mm M wide open:
Looks good, though I see nothing in this scene to invoke CA or PF at this stage(see: highlights and OOF regions such as branches with back-lighting etc.)

QuoteQuote:
the M 200mm is under appreciated. Its wide open performance knocks spots off the 85mm for CA. Bokeh may be another matter entirely, and for portraits the M 85mm is no doubt better, but as a tele lens, the M 200mm is not too shabby.
There's no doubt on this lenses sharpness, I've always been impressed with Pentax's old optics myself.

QuoteQuote:
To be honest, I'd be surprised to hear a zoom on a TC outperformed a tele on a dedicated TC
Assuming you meant a TC on zoom vs a TC on a prime? I think the issue here is where certain glass and coatings respond better to a specified teleconverter than others. In which case, most of the none ED Pentax glass tend to react with CA and PF in mind with a TC installed. A phenomenon that I've experienced with both 67 and PK Mount lenses alike. And though respond worst than others, I think the issue almost always comes down to our own tolerances in the end. Keeping in mind that CA and PF can be dealt with in many cases, the issue is often seen as a minor discrepancy.

QuoteQuote:
I've just read the Pentax T6-2x guide and it sounds like it was designed for the M 135 to M 300 range of lenses.
Aren't those 67 TC's?
09-05-2010, 04:17 PM   #13
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I've never used a 2x TC with my M200/4, but I have my doubts. I've got a 1.5x TC, and the M200/4 is the only lens (out of a dozen or so) with which it (barely) beats the results from simply cropping. My very cheap/subpar Samyang-made 500/8 also beats the results of cropping from 200mm, but by a larger margin. If the 200+1.5xTC only barely beats cropping (and only stopped down), I rather doubt the 200+2xTC would manage to beat it by a larger margin. So I'd have the expect that my Samyang mirror would beat the 200+2xTC, and a better mirror would beat it by a larger margin. The donuts don't really bother me, though. If they did, I guess I'd have to ask myself how much sharpness I was willing to give up in order get rid of the donuts.
09-05-2010, 05:51 PM   #14
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Thanks Marc, as a matter of interest, whats the TC you used?

PS nice landscape paintings on your Zenfolio site, sorry to compliment you again!
09-05-2010, 10:15 PM   #15
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Thanks! The TC is the cheaper Kenko one. I figure a cheap 1.5x TC might be similar in terms of loss of IQ to a more expensive 2x one.
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