[lesmore49]

I have been thinking about one of these Mirror lens for my Pentax K10D and KM bodies.

They don't seem to be readily available in Canada, so if I did buy one I would probably get this make of lens, from Adorama as I've read positive reviews about Adorama.

Here's an example of the type of lens that I'm considering.

50063PK Pro-Optic 500 f/6.3 Mirror Lens for Pentax K SLR Cameras

Some of the things I have rolled around in my mind and frankly I still have questions include the following :

• Clarity- I have the Pentax 55-300 lens and I'm very happy with the excellent clarity of detail that this lens provides. On the digital of course it is equivalent to a 450 mm...the 500 Mirror I guess would be the 35 mm equivalent of a 750mm...significantly more. QUESTION: How does the 500 Mirror compare in clarity of picture to the Pentax 55-300 ? Is it as good ?
• Depth of Field- I have read that the Mirror lenses have a very narrow depth of field. QUESTION: I generally use at least F 8 on my outside shots. This lens in the advert is a F 6.3. Is it fixed at this F stop only...or can I adjust the F stop to F 8, and higher ?
• Durability, robustness of construction: QUESTION - At $ 159 I have to wonder how well constructed would a Mirror lens be ?
• Wildlife Pictures: QUESTION-I would plan to use this lens for wildlife pictures...owls, eagles, deer, etc...sometimes they move fast...how would this lens handle that kind of action ? But on the other hand, I also take a lot of pictures of wildlife that sit, stand for good lengths of time.
• Picture Quality Examples- Could anyone post samples of their work with this lens? Thank you.
• User Experience: QUESTION: I have read Adorama's user experience with this lens. Some seem to absolutely love the Mirror lens, some don't. If you have one of these lenses what do you find the pros and cons with it.

• Operation of Mirror lens: QUESTION: Are there any particularities when using a mirror lens ? What is the best method for using one ?
  • Tripod: I have a Leitz Tiltall tripod...very heavy duty, used to use it with my Mamiya medium format. Also have a Giotto Monopod...is it recommended to use a support like these? I generally try to use at least 1/00th of a second with my 55-300 ..handheld...with this would it be able to produce a sharp pix at 1/750th of a second and higher.

Thanks for your input.

Les

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Last edited by lesmore49; 02-17-2010 at 02:53 PM.

[lesmore49]

No one have a mirror lens ?

[justDIY]

search for "the mirror lens club" ... there's a lot data about various mirror lenses in there, and plenty of great pictures.

[lesmore49]

search for "the mirror lens club" ... there's a lot data about various mirror lenses in there, and plenty of great pictures.

Thank you. I'll check that out.

[jogiba]

[yt]http://www.youtube.com/watch?v=oKO5f5RFatA[/yt]

[yt]http://www.youtube.com/watch?v=kgRROQYmjMM[/yt]


800mm F8 w/hood

[WillCarney]

Worth it? Depends.

I have a 500mm f/8 lens. The depth of field on focus is real tight. That is your focus area is very small with foreground and background objects out of focus with very little in focus. It is also very dark and can not be used very well in low light or night time without longer exposures. They are usually lighter in weight than an equiviliant 500mm lens on the positive side.

In saying all that, I have used it for wildlife shots to some success.
Mine is also a T-Mount so I can use it on any camera.

William

[ivoire]

Tamron 500mm 55BB f8, Tamron 500mm 55B f8, Tokina 500mm f8 and Sigma 600mm f8 offer the best IQ (in that order)

[MRRiley]

First off. The lens you linked to is a T-mount lens which requires an adapter to mount to your Pentax camera. They sell the same lens for every camera brand and just include an adapter in the appropriate mount. To answer your other question, it's a straight f6.3... no way to adjust the aperture (but this is typical of most mirror lenses).

ProOptic lenses are an off brand concern with nowhere near the quality of Sigma, Tamron, Tokina and the like. They might be better than Quantaray (Ritz's house brand) but it's hard not to be better than Quantaray.

You are probably better off buying a good teleconverter for your 55-300mm...

Mike

[aka]

This was the lens that made me realize my k10d was back-focusing. Here's one of the better shots I've managed with it. IIRC, this is uncropped so he was pretty close (they are usually more shy).

The f6.3 aperture is nice, IMO. On one hand, the depth of field close up is razor thin (a "half duck" thick). On the other hand, why would you be shooting with this lens if the subject was close enough for one of your others and more important, the focus confirmation still works at f6.3 in any light that will give you a reasonable shutter speed. This isn't really true with the f8 lenses. F6.3 also seems to be the bottom limit of my split-focus screens (both an ebay one and my modified ME Super screen).

Also, I don't know if this is a property of all T-mount lenses but my Rokinon seems to focus well past infinity which is annoying for obvious reasons.

One more PS- Mine came from overstock.com and was only around $125 shipped with the pentax adapter. Some places don't include it.

PS- some sort of homebrew or commercial shade really helps with contrast. I use a modified black plastic plant pot.

[newarts]

...
Some of the things I have rolled around in my mind and frankly I still have questions include the following :

I have the Rokinon version of the 6.3 lens and have compared it to the 55-300.

• Clarity- I have the Pentax 55-300 lens and I'm very happy with the excellent clarity of detail that this lens provides. On the digital of course it is equivalent to a 450 mm...the 500 Mirror I guess would be the 35 mm equivalent of a 750mm...significantly more. QUESTION: How does the 500 Mirror compare in clarity of picture to the Pentax 55-300 ? Is it as good ?
  it is not as sharp as the 300 but this can be corrected with Deconvolution software like Focus Magic.
  
• Depth of Field- I have read that the Mirror lenses have a very narrow depth of field. QUESTION: I generally use at least F 8 on my outside shots. This lens in the advert is a F 6.3. Is it fixed at this F stop only...or can I adjust the F stop to F 8, and higher ?
  
  The DOF is no worse than any other lens at 6.3. The aperture is fixed at 6.3 but I don't see that as a problem.
• Durability, robustness of construction: QUESTION - At $ 159 I have to wonder how well constructed would a Mirror lens be ?
  
  The construction is excellent.
• Wildlife Pictures: QUESTION-I would plan to use this lens for wildlife pictures...owls, eagles, deer, etc...sometimes they move fast...how would this lens handle that kind of action ? But on the other hand, I also take a lot of pictures of wildlife that sit, stand for good lengths of time.
  The lens is light & easy to handle, but any 500mm lens is extremely difficult to hand hold.
  
• User Experience: QUESTION: I have read Adorama's user experience with this lens. Some seem to absolutely love the Mirror lens, some don't. If you have one of these lenses what do you find the pros and cons with it.

In my experience this lens has lower contrast than the 55-300 but that is fixable in post-processing.

• Operation of Mirror lens: QUESTION: Are there any particularities when using a mirror lens ? What is the best method for using one ?
  • Tripod: I have a Leitz Tiltall tripod...very heavy duty, used to use it with my Mamiya medium format. Also have a Giotto Monopod...is it recommended to use a support like these? I generally try to use at least 1/00th of a second with my 55-300 ..handheld...with this would it be able to produce a sharp pix at 1/750th of a second and higher.
    Maybe, but those conditions may be rare I think.

I seldom use this lens but am glad I have it.

Thanks for your input.

Les

Dave in Iowa

[Entropy]

I have both this lens AND a Sigma 50-500 "Bigma"

It is a very situational lens.

Cons:
Fixed unchangeable aperture
Donut bokeh
Manual focus (not good when combined with shallow DOF)
Slow (focus confirmation doesn't work too well)
Contrast issues, REALLY needs a lens hood

Pros:
Unbelievably small and light for a 500mm lens

That one pro alone is enough to make up for the cons in the right situations. This lens requires quite a lot of skill to use to its fullest extent.

It might be easier with the improved live preview capabilities of the K-7 or K-x - it's NOT easy to focus properly with a K20D.

[Marc Sabatella]

This was the lens that made me realize my k10d was back-focusing.

??? that term applies to autofocus. Not relevant to mirror lenses. What you might be referring to is a discrepancy between the amount of DOF you see in the viewfinder as compared to in the actual shot; this is an unfortunate fact of life with most modern focus screen designs. Usually an issue only at very alrge apertures, but I could imagine it also showing up with a 500/6.3 because the DOF is probably at least as thin with faster "normal" lenses.

the focus confirmation still works at f6.3 in any light that will give you a reasonable shutter speed. This isn't really true with the f8 lenses.

I'd call it "sort of" true - I can get a focus confirmation with my 500/8 about as often as I'd expect (which is to say, often enough to be sort of useful, if less often that I would with other lenses).

Also, I don't know if this is a property of all T-mount lenses but my Rokinon seems to focus well past infinity which is annoying for obvious reasons.

From what I understand, it's a property of mirror lenses in general, to deal with the possibility of thermal expansion/contraction or something like that.

[newarts]

...

Also, I don't know if this is a property of all T-mount lenses but my Rokinon seems to focus well past infinity which is annoying for obvious reasons. ...

There are 3 little screws on the side of the T-K adapter. Loosen them, turn the adapter on the lens until infinity focus is correct. Tighten them.

Dave in Iowa

[aka]

??? that term applies to autofocus. Not relevant to mirror lenses. What you might be referring to is a discrepancy between the amount of DOF you see in the viewfinder as compared to in the actual shot; this is an unfortunate fact of life with most modern focus screen designs. Usually an issue only at very alrge apertures, but I could imagine it also showing up with a 500/6.3 because the DOF is probably at least as thin with faster "normal" lenses.

If the auto-focus is back-focusing, so ALSO will be the focus- confirmation dot; it is the same mechanism. You are of course correct that a thin DOF really highlights any backfocusing issue (which was my point); it was also super apparent with my manual pentax 50mm f1.4 at large apertures. I've adjusted the back focus through the firmware and am pretty happy with the results. Having the focus confirmation spot on makes this lens a lot more useful.

I'd call it "sort of" true - I can get a focus confirmation with my 500/8 about as often as I'd expect (which is to say, often enough to be sort of useful, if less often that I would with other lenses).

If I manually stop down another lens to f8, my split focusing screens pretty much black out and the focus confirmation gets real sketchy without good light. I'm saying that with the f6.3 mirror, both the focus confirmation and the split screens work very reliably (provided the camera is not back-focusing to begin with). I think the ability to actually focus in a variety of lighting situations is a reasonable trade-off for a narrow depth-of field.

BTW, I could shim the split-focus screen on my k10d a bit as it back-focuses slightly compared to the focus-confirmation dot which is spot on but this, again is something I only really notice with this lens. It is simply a matter of practice to remember how to line up the split image. (ie, catch the focus from the front and not from the back)

From what I understand, it's a property of mirror lenses in general, to deal with the possibility of thermal expansion/contraction or something like that.

Ahh, interesting. I think I'll add some strips of tape and mark where infinity is. Mostly, so I can set it at infinity quickly but it would also be interesting to see if it varies appreciably.

[aka]

There are 3 little screws on the side of the T-K adapter. Loosen them, turn the adapter on the lens until infinity focus is correct. Tighten them.

Dave in Iowa

Brilliant! thanks.