Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-14-2009, 02:55 PM   #1
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
Quantaray 600-100 zoom, other long tele ramblings

Still thinking about cheap & light long tele options. I've got some samples, and a asking for other.

I happened to run into a 600-1000 T-mount zoom at a local (non-closing) Wolf. I was kind of shocked at how light it was given the size. They wanted $113. Only had time for a quick test - handheld at that (but crouched and leaning again a wall and other supports). CA was quite bad, but sharpness was "OK". I'm guessing better than, say, the Tamron 70-300 with a 2X TC. Here a shot at 600mm:



And here's a 100% crop:



Passable for a cheap 600mm lens handheld, I'd say. It was much worse at 1000mm, and while I'm sure a tripod would have helped, the kind of softness I saw (largely CA-induced) wasn't going away that easily. Plus f/16 is pretty darn limiting. I'd probably treat it as a 600/9.6 prime if I got it.

I'm still trying to find more sample images form the cheap but widely available 500/8 mirror lenses out there (Samyang/Phoenix/Opteka/Vivtar). I know, everyone warns against these, but I've seen so few *actual images*. Many negative comments I've seen clearly are about mirror lenses in general, or long telephoto lenses in general, rather than really comparing these to other options. While I don't disagree that long mirror lenses are hard to use, it is by no means impossible, and I was actually perfectly happy with the Sigma 600/8 that I was borrowing for a while. A bit of contrast enhancement in PP and images were as good as any tele lens I've used. It was just heavier than I wanted (2 lbs +), and even should I decide to buy one, it's hard to find and correspondingly more expensive than I'm willing to pay. By all accounts, the Tamron 500/8 is as good and significantly lighter, but is also kind of hard to come by, and still heavier than I'd prefer.

Anyhow regarding the cheap ones, it's really hard to know just how bad they are. One person sent me samples which were indeed clearly terrible - enough to make me wonder if it was a defective unit. Although I've read that the skylight filter is part of the optical design - the lens is *not* to be used without it. So I wonder if at least some of the bad experiences people have reported were from folks who didn't realize they needed to use the filter. Either that or there is huge sample variation, because other samples I saw were much better - maybe only slightly softer than the Quantaray above, but with less CA, more or less making it come out even. But I've seen so few samples, it's really hard to get a sense of it.

People often tell me I'm better off using a TC on my M200/4, but I'm so far not that impressed with using my Kenko 1.5 SHQ. At the equivalent of f/9.5, it's OK, but still not that long of course. Does anyone any recommendations for 2X TC's that work especially well with this lens in their experience?

Yes, of course I know none of these are anywhere near as good as a Bigma or a good 400mm prime. But I'm not interested spending that kind of money or carrying that kind of weight, and am willing to pay a penalty in performance.

So, does anyone have any actual photographic evidence as to whether the cheap 500mm mirrors or M200/4 + 2X TC can get me at least clsoe to the level of that Quantaray zoom?

05-14-2009, 03:20 PM   #2
F16
Senior Member




Join Date: Feb 2009
Location: U.S.
Posts: 106
Other options you could consider would be a 400mm 6.3 or 500mm F8, either would be a bit lighter than a 400mm 5.6 if you're trying to avoid that, and even cheaper than this 600mm-xxx zoom and would probably be similar or better optically even with a 1.4x TC. You lose the zoom option, but then you said you'd probably think of this as a 600mm lens anyway. A 400mm 5.6 can be found at a similar price to this Quantaray lens also, though it will weigh 2.5-3 lbs.
05-14-2009, 03:24 PM   #3
Senior Member
scatron's Avatar

Join Date: Jun 2008
Location: Sandy, Utah
Photos: Gallery | Albums
Posts: 299
QuoteOriginally posted by Marc Sabatella Quote

I'm still trying to find more sample images form the cheap but widely available 500/8 mirror lenses out there (Samyang/Phoenix/Opteka/Vivtar). I know, everyone warns against these, but I've seen so few *actual images*.
Only images I have uploaded using a Tokina 500/8 mirror lens are of the moon:

Flickr: zaui's stuff tagged with tokina500mmf8mirrorlens

I can see if I have any others I can upload.
05-14-2009, 08:03 PM   #4
Veteran Member
Abbazz's Avatar

Join Date: Nov 2006
Location: Aotearoa
Posts: 531
Marc,

Here is a piece on advice on long focal lenses. I have quite a lot of them, including some crappy lenses and too few very good ones, because my budget is rather limited.

First, about mirror lenses. We all know that the F-stop value of a lens is the theoretical aperture calculated by dividing the focal length by the diameter of the lens. For most lenses, this is a good approximation of the actual measured aperture (T stop). But not for mirror lenses, which have a secondary mirror located right in the middle of the front element. This secondary mirror and the transmission losses due to the less than perfect reflections on the mirrors make the T-stop about 1 stop slower than the F-stop. In other words, the actual aperture of a 500mm F/8 mirror lens is T/11. Even a "fast" 500/6.3 is in fact a T/9.1 lens.

One of the main arguments in favor of mirror lenses is that they are small and lightweight. Maybe, but they also have a very limited aperture compared to refractive lenses. Have you ever seen a Russian 500/5.6 lens? I wouldn't call it small or lightweight, and it's only a T/8.0 lens! That said, mirror lenses can have quite acceptable image quality. Due to their particular construction, mirror lenses have no or very little chromatic aberrations. I suggest you look for a relatively short focal length, with the fastest aperture you can find, as this kind of lens will be much more usable than either a long focal length with a very limited aperture, or an enormous lens with an acceptable aperture. I have a Tamron 350/5.6 mirror lens (actual aperture: T/8.0), which is a very sharp lens. The famous "donut" bokeh of mirror lenses can produce some spectacular images if used with taste. Here are some pictures of mine, taken with the Tamron 350/5.6:







Second, about the el-cheapo supertele lenses. They come in many flavors (Phoenix, Quantaray, etc.). The most common are either the 600-1000 zooms or the 400/6.3 and 500/8 prime lenses. They are cheap, because they have simple optical construction (usually an achromatic doublet, that is 2 elements in one group for the prime lenses) and they do not feature any fancy low dispersion glass. They are not much heavier than mirror lenses but image quality is not very good, mostly due to chromatic aberrations. If you are interested in these, I suggest you look for the better ones, like the Novoflex Noflexar (most common are 400/5.6 and 600/8) or the Leitz Telyt (most common are 400/6.8 and 560/6.8). The Noflexar and Telyt lenses are both quite long as they are long focal lenses and not telephotos, but the lens body can be dismantled in 2 or 3 pieces for transport. Check the website of master wildlife photographer Douglas Herr to get an idea of what it's possible to achieve with a Leitz Telyt (and those are not as expensive as you might think... I just got a 400mm with T-mount adapter for $350 on eBay).

The last reasonable option option IMHO is to buy a modern telephoto lens with low dispersion glass. You will get the highest image quality and fastest aperture. Of course, the price tag will make you faint, especially for lenses over 300mm. The only Pentax lens I could (barely) afford in this category was the F* 300/4.5 (I paid about $1000 for it), which is certainly my best telephoto by far (and also my most expensive one): superb image quality, lovely colors, ultra low chromatic aberrations... I also have the Tamron Adaptall 2 300/2.8 telephoto (bought it for about $450 from Keh a few years ago). It's a nice lens, fast and well built, but still a notch below the Pentax in image quality. As it is a fast lens, I use it mainly with the Pentax 1.7X AF adapter, which turns it into a 510/4.5 autofocus lens. But the main reason I don't use it as much as the Pentax is that it is too bulky and heavy to handheld or to carry into my hand luggage for plane travels.

And what about the older telephoto lenses? I have a pair of old fashioned behemoths: the Takumar 500/4.5 and the Tamron 200-500/5.6. I don't use them much. Both have acceptable resolution, but they do not feature low dispersion glass, which means they exhibit a lot of chromatic aberrations wide open. So you have to close down the aperture at least 2 stops to get good image quality, which means shooting at F/11. Then why not use the Pentax 300/4.5 + 1.7x teleconverter or the 400/560mm Leitz Telyt instead, which are both much lighter and easy to carry than the aforementioned prehistoric beasts?

That's my 2 cents on the matter.

Cheers!

Abbazz


Last edited by Abbazz; 05-14-2009 at 10:19 PM. Reason: Fixing links
05-14-2009, 09:05 PM   #5
Loyal Site Supporter
pacerr's Avatar

Join Date: Jan 2008
Location: Henry, TN
Photos: Gallery | Albums
Posts: 2,910
> "Although I've read that the skylight filter is part of the optical design - the lens is *not* to be used without it. "

Marc, that's an interesting statement. I'm curious as to where you found it stated that way. I'm re-reading the instructions for the Samyang 500/F8 and I don't understand the only note I see as being "mandatory" or having to do with the optical formula.

Regarding the 1A Skylight filter: "This filter should be used whenever no other filter is necessary."

I've read that as being permissive - perhaps a subtle inflection in translation. I'd be happier if it was worded " ...MUST be used whenever no other filter is PRESENT." implying that the UV filter AND ALL OTHERS have an optical role and one of them MUST be inserted, as well as a caution not to use the lens without a corrective filter of some sort.

But I'll post some comparison shots tomorrow and see if I can see a difference.

Luego, H2
05-14-2009, 09:41 PM   #6
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
Original Poster
Thanks, I'd be curious to see those! I don't remember the specific sites where I read about the filter being part of the optical design, but I saw it in several places. A couple just mentioned it without giving any reasons why it should be so, but explained why pretty clearly. If you put any piece of glass between a lens and the sensor, it affects the optical path pretty significantly (compared to putting the glass in front of the lens). So if the lens did exactly what it was supposed to do without an additional filter, adding a filter would screw it up. Since they want to provide the option of using a filter, they have to design the lens so that the lens completes the optical design rather than screws it up. Meaning you need a filter in place at all times. This is supposedly true of *any* mirror lens that takes rear filters, not just the cheap ones. Although I took pictures using the Sigma mirror lens without the rear filter (before reading about this), and I can't say i could tell the difference. But at least one review of one lens - I think it was the either the Samyang or the Pro-Optic - said it made the difference between being merely "not sharp" and "seriously not sharp".

Realistically, while I've seen very few samples from any of these inexpesive mirror lenses, the few I've seen from the Pro-Optic look better on the whole than the few I've seen from the Samyang.

Abazz: thanks for the insight, and those great-looking pictures! I hadn't seriously considered the 300/5.6-ish mirror lenses, but maybe I should.
05-14-2009, 11:01 PM   #7
Veteran Member
Abbazz's Avatar

Join Date: Nov 2006
Location: Aotearoa
Posts: 531
QuoteOriginally posted by Marc Sabatella Quote
I don't remember the specific sites where I read about the filter being part of the optical design, but I saw it in several places. A couple just mentioned it without giving any reasons why it should be so, but explained why pretty clearly. If you put any piece of glass between a lens and the sensor, it affects the optical path pretty significantly (compared to putting the glass in front of the lens).
Regarding the rear filter being mandatory, it's simple optical theory. A glass filter will increase the length of the optical path by approximately 1/3 of its thickness. If the filter is located in front of the lens, the distance between the lens and the subject being much bigger than the filter's thickness, the influence of the filter can be neglected. When the filter is located behind the lens, then the thickness of the filter is not negligible compared to the distance between the lens and the image plane, and the ability for the lens to focus correctly may be affected. Of course this will be more evident for wide angle lenses, which have less depth of focus, but it can also affect long focal lenses. Here's a link to the relevant pages in Doug Hart's book, The Camera Assistant, Focal Press Publisher.

QuoteOriginally posted by Marc Sabatella Quote
Abazz: thanks for the insight, and those great-looking pictures! I hadn't seriously considered the 300/5.6-ish mirror lenses, but maybe I should.
Tanks. The Tamron SP 350/5.6 is a wonderful lens, very compact, but it's becoming quite rare and expensive nowadays.

Cheers!

Abbazz

Last edited by Abbazz; 05-15-2009 at 02:52 AM.
05-15-2009, 08:49 AM   #8
Loyal Site Supporter
pacerr's Avatar

Join Date: Jan 2008
Location: Henry, TN
Photos: Gallery | Albums
Posts: 2,910
Cat curiosity

[QUOTE=Abbazz;596150]Regarding the rear filter being mandatory,

Thanks, Abbazz, an interesting article.

[Darn it, Marc, I never expected to fiddle with this lens again, much less have to actually THINK about it!]

But now I'm really curious about 'cats' and I have three questions:

- When I went to do the promised comparison this morning I discovered that there were two rear filters provided with this "new" Samyang 500/F8 cat lens. (Actually, it's not new, I've just never been interested enough to shake out the box.) There's one 2x ND and one 4x ND still in the original plastic envelops and NO clear/UV filter of any kind provided although the tiny manual mentions the use of 1A, Y52. O56 and R60 filters. So, no comparison between NO filter and 1A filter will happen today - but I may try NO, 2x and 4x NDs just for fun.

- If the presence of SOME filter is ALWAYS necessary, how is it that Samyang would totally ignore providing that 1A or at least mentioning that it was required in their otherwise reasonably comprehensive instructions for this widely distributed lens? It's sold under enough different brands over the years that SOME re-seller would surely have demanded that this be covered and/or provided with the lens.

- The article emphasizes the greater importance of the rear filter with W/A lenses. Is it possible that at 500mm and this price point that it just isn't considered necessary? Even so, for the small cost of a ~27mm piece of clear glass and a few lines of text, I can't imagine why some manufacturer wouldn't cover this marketing advantage when IQ seems to be such a big issue with economy mirror lenses.

- Is this issue addressed in the Tamron Adaptall SP 300/2.8 knowledge base? It should certainly be common knowledge for that lens or many others of that nature. Or do I just need to stop being obstinate and move up to more expensive tele lens? (Uhhh . . . that's a rhetorical question by the way.)

H2

05-15-2009, 11:28 AM   #9
Pentaxian
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,864
I assumed my Korean-made Vivitar 500/8 mirror was the same as the Samyang but maybe not. It takes a 30.5 mm filter and includes a skylight filter. The manual says nothing about a filter being required, it just cautions about using a front and rear filter at the same time.
05-15-2009, 12:15 PM   #10
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
Original Poster
QuoteOriginally posted by pacerr Quote
- When I went to do the promised comparison this morning I discovered that there were two rear filters provided with this "new" Samyang 500/F8 cat lens. (Actually, it's not new, I've just never been interested enough to shake out the box.) There's one 2x ND and one 4x ND still in the original plastic envelops and NO clear/UV filter of any kind provided although the tiny manual mentions the use of 1A, Y52. O56 and R60 filters.
One of the articles I had seen specifically mentioned that issue regarding some lens or other - the necessary filter was not supplied with the lens.

Anyhow, sorry to resurrect this old pain for you. But you *know* you're curious now too :-)

BTW, I'm having no trouble finding relatively inexpensive older 400mm lenses, including the Vivitar 400/5.6, although I have no idea if there are different versions of this. Not sure where this fits in abazz's taxonomy, but I thought the sample I saw from you looked good...
05-15-2009, 12:19 PM   #11
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
Original Poster
QuoteOriginally posted by Just1MoreDave Quote
I assumed my Korean-made Vivitar 500/8 mirror was the same as the Samyang but maybe not. It takes a 30.5 mm filter and includes a skylight filter. The manual says nothing about a filter being required, it just cautions about using a front and rear filter at the same time.
OK, so what do you think of it? Have you tried it with and without the rear filter?

Just noticed earlier today (or just remembered - I probably knew but forgot) that you're in the Denver area. Maybe someday we could meet up and I could try a few test shots myself?
05-15-2009, 01:27 PM   #12
Pentaxian
Lowell Goudge's Avatar

Join Date: Jan 2007
Location: Toronto
Photos: Gallery | Albums
Posts: 15,400
I can't help but point out that there is a SMC 300mm F4 in th emarket place for $130. I don't care what TC you add, it has to be better than a quantaray
05-15-2009, 02:04 PM   #13
Pentaxian
Marc Sabatella's Avatar

Join Date: Sep 2006
Location: Denver, CO
Photos: Gallery
Posts: 10,686
Original Poster
I did see that, thanks. Thing is, I have the Tamron (OK, actually, another Quantaray) 70-300 as it is, and it does just fine *at* 300mm, so the only thing that interests me about it is that it would presumably do better with a TC than the 70-300 does. But thenm I'm then at the mercy of the TC as to whether the results are actually any better than the other options I'm considering or not. And if the TC is good enough to give me decent results with the K300/4, I'm guessing it would also do at least as well with the M200/4. Granted, 200x2 = 400mm which isn't 300x2 = 600mm, but still, it seems my first priority if I were go down that road would be to locate a good 2X TC, and see if using it with my M200/4 makes me more frustrated with the length or with the quality. And if it's length, next priority would be to decide if I could stomach the >2X increase in weight. And if I'm going to have a >2 lb 600/8, I'd want to know that not only was it better than the $113 Quantaray, but also at least as good as the Sigma 600/8 that did quite well for me when I had access to that.

So I'm not in hurry to buy a K300/4 on the speculation that it would all happen to pan out that way. However, it is a greta price, and I'll admit I've been tempted.
05-15-2009, 03:57 PM   #14
Pentaxian
reeftool's Avatar

Join Date: Dec 2007
Location: Upstate New York
Photos: Gallery | Albums
Posts: 8,157
I read all of these threads with interest because i'm also looking for some decent, affordable long glass. Pop Photo recently did a review of the Pro Optic 500 mirror and it was a pretty positive review. I have never used a mirror so i'm somewhat hesitant. I have used my 200/4 Takumar with a M42 2X Vivitar converter and the CA was the worse I have ever seen. The Tak without the converter is fine. That 300/4 is tempting but I have already spent this months LBA budget on the 10-17 Fisheye.
05-15-2009, 04:33 PM   #15
Loyal Site Supporter
pacerr's Avatar

Join Date: Jan 2008
Location: Henry, TN
Photos: Gallery | Albums
Posts: 2,910
OK, OK. Tomorrow I'll post a Super Tak 300/F4 with and without the TCs - I know I've got those. Mine's the M42 picked up for $135 late last year in Thornton.

Meantime, here's the Samyang 500/F8 with and without a piece of glass inserted in the rear (pardon the expression). Left side is barefoot per shutter speed. Judge for yourself whether or not it was beneficial although it WAS a 2x ND rather than a UV or 1A skylight. The results aren't impressive either way with this particular lens.

Dave, it IS a 30.5mm filter by conventional measure.

Marc, I posted some Vivitar 400/5.6 pix including TC shots on 05-06 titled "A fungus comparison". And I'd encourage you to take a close look at the Tamron 75-300 LD - so far, it's my top choice among the econ 300's. Minimal CA/PF, plays nice with TCs and IMO a little sharper than the S or T 70-300's.

This'd be a lot easier if we'd started this thread before I left Denver!

H2
Attached Images
 
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
2x, course, k-mount, lens, lenses, mirror, pentax lens, quantaray, samples, slr lens, tc, tele, wonder
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale - Sold: [Worldwide] Quantaray 100-300mm compact AF zoom for Pentax wallyb Sold Items 1 02-18-2010 10:13 AM
For Sale - Sold: Quantaray 70-300mm LD Tele-Macro ivoire Sold Items 0 12-16-2009 11:53 AM
Quantaray 70-300mm LD Tele-Macro? Gregor Pentax SLR Lens Discussion 2 12-07-2009 09:55 PM



All times are GMT -7. The time now is 01:28 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top