[Michael Piziak]

I've been trying to dig through some sample images on the net....

Anyone have any idea which lens would be the sharpest at 600mm, the Sigma Mirror 600mm F8 Lens Reviews - Sigma Lenses - Pentax Lens Review Database

or

the SMC Pentax 400-600mm Reflex Reviews - K Zoom Lenses - Pentax Lens Reviews & Lens Database


I see the Pentax has a higher sharpness rating here, but I was curious if the Sigma may be very similar or even better at the 600mm range since it appears to be like comparing a prime (the Sigma) to the Pentax (which goes from 400-600 and not considered prime I suppose) - ? The used price difference in the 2 is certainly significant....

I realize all the downfalls of such a mirror lens and would mostly be using it more or less as a toy to shoot shots at the bird feeder with a tripod....

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Last edited by Michael Piziak; 02-04-2023 at 04:32 PM.

[RICHARD L.]

This old Sigma 600 mm f/8 reflex is, let's say, a NO-NO. I had one with a Minolta SR mount that proved to be a "DISASTER", don't touch this even with a 10 foot pole. It was full of aberrations, vignetted a lot, was unusable facing a light source because it flared so much, the bayonet flange was too thin so the lens kept wobbling and so on and so forth. Don't lose even a penny on this wreck.


Regards

[TwoUptons]

I'll note without having owned either that the lens review database is entirely subjective, and caution should be taken when comparing lens ratings...

-Eric

[GUB]

Here ya go. Please note I like both lenses. Light here overcast so lovely colours but problematic @ 1/250 and ending up about iso 1600 to 3200 after lightening in post. A light dose of profiled denoise from Darktable. Wind an issue.
Sample variation and user error would cover 95% ot the comparisons here.
The most obvious thing is that extra stop of light is the game changer.
My only comment is these old examples of mirrors are far better than the generic range currently available.
On the K-1

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[Michael Piziak]

This old Sigma 600 mm f/8 reflex is, let's say, a NO-NO. I had one with a Minolta SR mount that proved to be a "DISASTER", don't touch this even with a 10 foot pole. It was full of aberrations, vignetted a lot, was unusable facing a light source because it flared so much, the bayonet flange was too thin so the lens kept wobbling and so on and so forth. Don't lose even a penny on this wreck.


Regards

I think it would be *very* useful to all Pentax users that are considering reflex lens, that is if you would make your review of owning the lens here on Pentaxforums - please do so friend....

Also, I wander if you perhaps may have had a lemon copy of it - ? I'm particularly concerned with the mount to the Pentax k and wander if it makes a bad connection like you experienced with the Minolta....


Michael

---------- Post added 02-04-23 at 07:07 PM ----------

Here ya go. Please note I like both lenses. Light here overcast so lovely colours but problematic @ 1/250 and ending up about iso 1600 to 3200 after lightening in post. A light dose of profiled denoise from Darktable. Wind an issue.
Sample variation and user error would cover 95% ot the comparisons here.
The most obvious thing is that extra stop of light is the game changer.
My only comment is these old examples of mirrors are far better than the generic range currently available.
On the K-1

Wow, your copy of the Sigma seems to deliver better, or sharper I should say, photos than the Pentax 400-600mm.

I am somewhat scared away from this lens, though, after reading Richard L. posted above. Do you have any similar negative comments about it? Do you think maybe he came across a lemon copy ?

[GUB]

I think it would be *very* useful to all Pentax users that are considering reflex lens, that is if you would make your review of owning the lens here on Pentaxforums - please do so friend....

Also, I wander if you perhaps may have had a lemon copy of it - ? I'm particularly concerned with the mount to the Pentax k and wander if it makes a bad connection like you experienced with the Minolta....


Michael

---------- Post added 02-04-23 at 07:07 PM ----------


Wow, your copy of the Sigma seems to deliver better, or sharper I should say, photos than the Pentax 400-600mm.

I am somewhat scared away from this lens, though, after reading Richard L. posted above. Do you have any similar negative comments about it? Do you think maybe he came across a lemon copy ?

I don't consider my 400-600 to be less sharp than the Sigma. What you are seeing in the results is probably user error - it is so easy to slightly miss focus. Also an extra stop of noise denoised will soften things a little at this level.
A lot of people are negative of mirror lenses. The lenses are intolerant beasties that will punish you for the slightest misfocus - I did a thread with a theory on it not long ago - Mirror Lens Depth of Field - PentaxForums.com
Note that I wouldn't think of trying to nail the focus with the OVF. I tend to use live view and if handheld with a viewfinder loupe. But imagine if you are trying to handhold a refractor 600mm.
I also tend to work at base iso and pull up the image in post - this means I keep absolute control of the highlights which aids in keeping good contrast.
I use full frame and try to avoid cropping too much because sharpness is marginal - this doesn't bode well for using it on APSC.
Having said that here is the 400 - 600 on the Q (#1109) Adapted lenses tested on the Q : the reference thread - Page 74 - PentaxForums.com Now that is cruel and unusual punishment for a lens !
If you are planning to use it as in your OP you can prefocus a little - just be aware that merely being at the bird feeder may not place the bird in the plane of focus.
A lot of the success of your endeavour will be in the aethetics of your background - a bunch of donuts probably won't do it for you - you need an un- contrasty background.

[mlag]

In general my pentax 400-600 seems to beat my other mirror lenses in sharpness, including my sigma 600 (which is in a well used condition unfortunately).

Pentax 400-600 + topaz (from 20 meters roughly)

In dim light, f8 and f12 will make a huge difference, especially handheld, with f12 the shutter time an ISO will get very uncomfortable ...,
f12@600 is indeed a disadvantage of the pentax, but I would not blame it on intrinsic sharpness!

I prefer also lcd-liveview+loupe over viewfinder+O-ME53 to nail focus on mirror lenses, manual focus is tedious as you seem always lacking sufficient light.

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Last edited by mlag; 02-06-2023 at 08:23 AM.

[RICHARD L.]

I think it would be *very* useful to all Pentax users that are considering a reflex lens, that is if you would make your review of owning the lens here on Pentaxforums - please do so friend....Also, I wonder if you perhaps may have had a lemon copy of it - ? I'm particularly concerned with the mount to the Pentax k and wonder if it makes a bad connection like you experienced with the Minolta....

I purchased this Sigma 600 mm f/8 Reflex lens hoping to be able to realize a series of pictures of the City of Montreal. At the time, my daughter was studying Biochemistry at McGill University and we rented an apartment on Sherbrooke Street on the 14th story of a tower near Lafontaine Park. We had an extended view of Sherbrooke Street reaching into Eastern Montreal on one side and into Downtown Montreal on the other side. We had access to the roof of the building and we could take pictures of the Montreal fireworks and Jacques Cartier Bridge towards the South Shore. A long telephoto would thus make it possible to make magnificent images all around the city.

From our balcony, I mounted my Minolta X-700 + Sigma 600 mm f/8 Reflex on my solid Manfrotto 028 tripod. I took pictures in bright daylight on Kodacolor 200 negative film. East along Sherbrooke Street towards the Olympic Stadium, West towards Downtown, etc. I moved to the roof and finished my 36-exposure roll. All the images were "DISASTERS". I had been taking pictures for over 25 years then, so I knew what I was doing. The pictures were all fuzzy, uneven, sometimes had double edges, always flary and unacceptably rendered. I tried a few other rolls with it in Quebec City with always terrible results : no sharpness, excessive flare, etc. Plus the bayonet flange was too thin on the lens and the fit on any of my 5 Minolta bodies at the time was very bad. The lens wobbled with all my camera bodies.

Not being patient, I bought a new Minolta 500 mm f/8 Reflex lens in a Montreal Photo Store on Rosemont Blvd I knew, located just North and West of the Botanical Gardens. What a difference ! The Minolta Reflex (which I still have to this day) was sharp and contrasty, needed solid support on my Manfrotto but gave me extraordinary results (notably a very sharp vertical rendering of Sherbrooke Street extending from the Charles de Gaulle monument to a few streets before the Olympic Stadium - the picture was full of millions of details, even down to cars' license plates numbers from 1/4 mile away). Around Quebec City the Minolta 500 mm Reflex produced very nice images of fields of wheat (with beautiful doughnuts in OOF areas) and of various sunset settings. So, can a Reflex lens produce exciting images : YES. But it takes a good lens from a reputable maker. Maybe the Sigma was "below par", a lemon or defective but I never bought another "jobber's lens" from that day on.

[marcusBMG]

I have compared the sigma 600mm to both a refractive 600mm f8 (tokina made), and to the tamron SP 500mm f8 mirror.
At best I was able to get results from the sigma competitive with both the refractive 600m and the tamron 500mm. But overall I would expect to get more consistently better results from either of the others. I found the sigma 600m more user unfriendly in terms of focussing etc, and general rendering. The tamron has the advantage (imo) of 500mm vs 600mm - that 100mm difference gives very little extra reach in terms of fov but distinctly more problems with focus, vibration/shake etc. The refractive lens has the advantage of stopping down to f11, when it was consistently better. I should be balanced and mention that the mirrors have way better CFD.
I wouldn't bother with the sigma, the tamron deserves it's rep as one of the best mirrors out there while the sigma is known for inconsistent quality. There are that many around if you search you should be able to pick one up for a hundred bucks or less.

[GUB]

I have compared the sigma 600mm to both a refractive 600mm f8 (tokina made), and to the tamron SP 500mm f8 mirror.
At best I was able to get results from the sigma competitive with both the refractive 600m and the tamron 500mm. But overall I would expect to get more consistently better results from either of the others.

Plus one on that - the mirrors are intolerant of mis focus and bad background choice. This means results are more hit and miss.
Also testing them on distant objects aggravates the lack of contrast situation - the atmosphere isn't as stable and clear as we presume.
A black mark for the 400-600 is it's minimum focusing distance of 3 metres. The sigma 600 is 2 metres and the Tamron 500 is 1.7 metres - both 1:3.

[Michael Piziak]

Note that I wouldn't think of trying to nail the focus with the OVF. I tend to use live view and if handheld with a viewfinder loupe.

.

Thanks for all your very useful comments from your experience. I have never used it, but would the "focus peaking" be useful with mirror lens like the Sigma 600mm - ?

---------- Post added 02-05-23 at 04:41 PM ----------

I prefer also lcd-liveview+loupe over viewfinder+O-ME53 to nail focus on mirror lenses, manual focus is tedious as you seem always lacking sufficient light.

Thank you also for your insight. I'm not familiar with what this "loupe" method of focussing is, can you or someone else explain it to me. I have the K-S2 also, and wander if this "loupe" method of focussing can be done with it...

---------- Post added 02-05-23 at 04:45 PM ----------

I purchased this Sigma 600 mm f/8 Reflex lens hoping to be able to realize a series of pictures of the City of Montreal.

Thanks with all your comments on your experience with the Sigma. I seen a video, where the user suggested, with the Sigma 600mm, to take photos where the subject and its background has distance between them to minimize the bokeh. I think that perhaps your attempts to take photos of the City of Montreal might just be the worst scenario of trying to use a mirror lens where there tends to be a lot going on in the background...

---------- Post added 02-05-23 at 04:48 PM ----------

I have compared the sigma 600mm to both a refractive 600mm f8 (tokina made), and to the tamron SP 500mm f8 mirror.
At best I was able to get results from the sigma competitive with both the refractive 600m and the tamron 500mm .......


.....Mirrors out there while the sigma is known for inconsistent quality. There are that many around if you search you should be able to pick one up for a hundred bucks or less.

I actually owned the Tamron & posted here about it in the past. I may have had a bad copy, but my Pentax 55-300mm lens made much better cropped photos than the Tamron did uncropped. & my copy of the Tamron looked emaculate.

[RICHARD L.]

Thanks with all your comments on your experience with the Sigma. I have seen a video where the user suggested, with the Sigma 600mm, to take photos where the subject and its background have distance between them to minimize the bokeh. I think that perhaps your attempts to take photos of the City of Montreal might just be the worst scenario of trying to use a mirror lens where there tends to be a lot going on in the background...---------- Post added 02-05-23 at 04:48 PM ----------

OTOH, the Minolta 500 mm f/8 Reflex performed admirably under the same circumstances, capturing myriad of details near (about 1/4 mile) and far (infinity). I can perceive the difference between an awesome precision optical instrument (Minolta) and a "dud" imitation of a Cassegrain telescope ...

Regards

[GUB]

Some close ups with the Sigma 600mm. Remember I am 2 metres from a subject with 600mm @f8 - just don't expect any dof!

[Michael Piziak]

I hadn't planned on buying the Sigma this evening; however, I just got an email that the seller reduced the price, on what he described as being in "great condition", reduced it to $85.
So what the heck, for $85 it will at least be a toy for a little while. Unless, of course, I find I don't like it at all right off, like I did the Tamnron 500mm reflex copy (or it's as bad as Richard L describes his copy as).....

I do have one question. This copy doesn't come with the various multi colored filters - they must have been lost along the way. Can such filters be purchased ?


Michael

[RICHARD L.]

Can such filters be purchased ?

LOL Just to taunt you a little more : probably not, this "lens" is too old. But I have a complete set of colored filters for my Minolta Reflex ... nah, nah, nah nah ! (just kidding)

Best Regards