Mirror! Mirror! -a guide to choosing and using Mirror lenses part two

400_500_600
Contax Zeiss 500mm f8 – Sigma 600mm f8 – Canon 100-400 mkll f4-5.6

In the picture above, you can see the obvious appeal!  In case you were wondering the lenses above are mounted on my collection of three Canon EOS3 film cameras. A fabulous body, review to follow. The tests were carried out with a Canon 5Dk3 – I just don’t have three of those!

 

This is a follow on article from my earlier comprehensive guide to choosing and using mirror lenses. If you haven’t already, I suggest you read that one first!

Contents

  1. Sigma 600mm f8 test
  2. Observations about using mirror lenses and questions that need to be answered
  3. Sigma 600mm vs Canon 100-400mm with 1.4x teleconverter (560mm up sampled) vs Zeiss Mirotar 500mm (up sampled)
  4. Overall conclusion and recommendations.
  5. Zeiss Mirotar gallery
  6. Appendix – test of two Vivitar mirror lenses
800px-Schmidt-Cassegrain-Telescope.svg
Diagram showing light path through a mirror lens (Camera on right)

Introduction – is the Zeiss still fairest of them all?

In part 1 of “Mirror, Mirror” I argued the case for using mirror lenses on digital cameras. Many of the faults inherent in this design can be compensated for both with the features of the latest digital cameras and digital image processing techniques.

With film cameras for example, it was very hard to accurately focus as at the fixed aperture of f8 – the split image rangefinder in the viewfinder would not work and the image would be very dark. With digital DSLR’s, live view can be used to more accurately focus. Some mirrorless camera bodies have manual focus aids such as “focus peaking”. It is also possible to buy adaptors for these lenses that communicate with the camera body so that when in focus the “focus confirm” light illuminates. Using one of these on a Sony A7 mkll would be interesting, as it has image stabilisation built into the body.

Mirror lenses tend produce low contrast images with a strong vignette or hotspot. Simple fixes in Lightroom that can be applied en-mass to all the images taken in seconds.

 

I previously tested the following lenses in descending order of preference.

Mirror lenses-21
Nikon –  Zeiss – Tamron
  • Contax / Zeiss Mirator 500mm f8 – Stunning! the best tested, high resolution, integrated hood, beautifully made, expensive – a properly engineered solution.
  • Tamron 500mm f8 – Very good value for money – recommended to try out (but you’ll wish it was the Zeiss!)
  • Nikon 500mm f8 – Poor value for money – noticeable hotspot – not recommended unless a bargain price.
  • Tamron 350mm f5.6 – (not shown above) Very poor sharpness and low contrast – not recommended (however suspicion that I had a bad copy)

This article is one of the most read on my blog, so I decided to update it with another two lenses.

This “part 2” article adds the Sigma 600mm f8 to the testing and I briefly tried the Vivitar Solid Cat 600mm f8 and the Vivitar 500mm f8. I then compared the Zeiss and Sigma to the Canon 100-400mm mk2 with 1.4x converter.

Sigma600

1. Sigma 600mm f8 Comprehensive Review

The Sigma 600mm Mirror lens was made with mounts for the popular brands of camera. Unlike the Tamron 500mm, available at the time and a direct competitor, the Sigma has fixed mounts rather than adaptors, which does make for a more robust fit, but of course makes it harder to find one to fit your camera. I bought a fixed mount EOS version. As you would expect it fits precisely without any movement.

600mm gives 12x magnification on a full frame 35mm DSLR body, or effectively 960mm 19x magnification on a Canon crop DSLR!

The challenge then is keeping this non image stabilised lens from wobbling – and a challenge it certainly is. While the lens is relatively small compared to a conventional 600mm lens it is much bigger than say the Canon 24-70f2.8, and it is noticeably more chunky that the Zeiss Mirotar  or Tamron 500mm.

Unlike the Zeiss 500mm that I have fitted with an aftermarket autofocus confirm adaptor, the Sigma is tricky to focus, to say the least. Hand held use is not really an option, not really because of camera shake affecting the final image – as with modern DSLR’s high ISO’s and high shutter speeds are not a problem, but with the image jumping around so much in the viewfinder, it really is hard to get critical focus. Live view based focus with 5x or 10x magnification is much more successful (but obviously not handheld). A tripod or beanbag is then essential. A beanbag is a very useful accessory with any mirror lens as it is lightweight to carry and damps movement very well – so long as you can find a bench/fence/bin/post/car to rest on!

Buying one is easy enough, there are plenty on ebay. I have seen these go from £100-220 depending on condition. I previously tried one of these in a shop, and it was truly dreadful, really low in contrast – while this is a trait of mirror lenses, it gets worse with age as dust and fungus builds up and the mirror coatings dull. Fortunately this particular example is considerably better than the one I had previously tried. When buying one then ideally it is best to try it or ask seller for sample images.

I decided to shoot images at Shoreham Harbour, on the South Coast of England near my home town of Brighton. There are cranes, ships, chimneys with lots of detail available to try to resolve and the opportunity to shoot across the water. I used a robust Manfrotto carbon fibre tripod, with geared head and there was little wind. This is the Power Station chimney at full frame, and then a crop. These are default settings in Lightroom. Notice the excellent histogram, one of the best I have seen for a mirror lens. This was taken on the beach side of the power station.

Sigma 600mm
Sigma 600mm default settings in Lightroom

Screen Shot 2015-09-07 at 18.30.02

Screen Shot 2015-09-07 at 18.25.04

The detail here is good, with the mesh fence clearly visible – remember this has only the Lightroom default of 25 “capture” sharpening applied.

Applying some Clarity, and doubling the sharpening level, with a mask and detail added with these settings…

Settings applied
Settings applied

.

Sharpening added
Sharpening added

The resulting image – is really very good! Think how small the wire mesh is here, and how far away it is.

Screen Shot 2015-09-07 at 19.56.17

Inspired by this initial image I returned to Shoreham and walked along the road opposite the power station and shot across the water.  I shot from 4 further positions and have highlighted these on Google earth images, with the camera directions and subjects so you get an idea of how far away the subjects were. I shot images deliberately with perspectives that would be difficult to achieve if closer, and the water makes that difficult to achieve anyway.

Camera position 1
Camera position 1

Here are some of the resulting pictures for Camera Position 1

Crane - Sigma 600mm f8
Crane – Sigma 600mm f8
Truck - Sigma 600mm f8
Truck – Sigma 600mm f8
Gravel Machine - Sigma 600mm f8
Gravel Machine – Sigma 600mm f8
Sigma 600Mm f8
Cylindrical Towers – Sigma 600Mm f8

 

 

 

 

 

Camera position 2

Camear-P-2

Sigma 600Mm f8
Crane Sigma 600mm f8
Sigma 600Mm f8
Digger Sigma 600Mm f8
Sigma 600Mm f8
Crane 2 Sigma 600Mm f8
Sigma 600Mm f8
Sigma 600Mm f8
Sigma 600Mm f8
Sigma 600Mm f8

Having inspected these images, my impressions are:

Good points

  1. It’s fun! Having a completely different perspective.
  2. It’s surprisingly good! Much better than expected after tweaking in Lightroom.
  3. There doesn’t seem to be much vignetting or a hotspot like the Nikon 500mm
  4. The contrast is better than I expected but still needs a little boost – though on some exposures I just pulled blacks down a little to darken the extreme shadows (and hide the noise!).
  5. There is little or no Chromatic Aberration (a characteristic of the mirror design)

However

  1. Focusing through the viewfinder is very difficult. It’s dark and DSLR’s have no manual focusing aid apart from “focus confirm” but that does not work with this lens.
  2. It is better to use “live view” but tricky to focus in bright light  – so a hood magnifier is recommended – I use the “Matin” version.
  3. The sensor in the 20MP 5D mk3 is clearly out resolving the lens – the images appear a little soft at 100% compared to my Canon “L” lenses – if you use a 12MP full frame camera this will be less of a problem – see later tests. A crop sensor with 10 MP+ will also show up the lack of resolution. Clearly then the resolution of a a 7D mk2 , a 5Ds or the Nikon D800 series will be far too much for this lens, which was of course originally designed for film.

Having experimented in Lightroom I have found the following settings useful.

Contrast +10  Clarity + 30

Sharpening + 50 but use the masking set to at least + 70 to reduce sharpening to edges only.

Overall this lens surprised me, it produces useable images with good contrast. What I am interested in is how the final images compare to the other lenses I have.

 

2. General points about mirror lenses and their use.

In the first review all the lenses performed quite well on the Canon 12MP 5D but with clear differences. The winning lens, the Zeiss 500mm Mirotar, performs well on the 5Dk3. The differences between a good mirror and a bad one is simply staggering. The Vivitar lenses I tested (see appendix) were appalling in terms of definition, contrast, colour, sharpness, while the Sigma was surprisingly good.

After this test and my other experiences of testing mirror lenses, a couple of questions remain.

 

Q1. How does the Sigma mirror compare to the Zeiss 500mm and Canon 100-400 LIS mk2 with teleconverter?

Q2. Is lens performance more closely matched when using a camera with a lower resolution sensor such as the Canon 5D 12MP on full frame.

Q3. Is it better to upsample the images from a shorter focal length?

Q4. Is it better to shoot at a lower resolution in camera when using a mirror

 

3. Comparison of Sigma 600mm f8 with Zeiss 500mm f8 and Canon 100mm-400mm f4.5-5.6 LIS mk2 upsampled

Q1. How does the Sigma mirror compare to the Zeiss 500mm and Canon 100-400 with teleconverter?

Canon 100-400mmf4.5-5.6 LIS mk2 tele zoom 

I recently bought this mk 2 optic (at £1750) which can be used with the Canon 1.4x teleconverter (£250). This gives very sharp results at 560mm on the 5Dk3 – but the autofocus slows considerably making it useless for moving subjects. On a crop Canon body this would gives 640mm without the teleconverter. If you can afford a £2k lens then there are considerable advantages, including autofocus, depth of field control and better sharpness and contrast than either of the mirror lenses tested, but it makes you look like a Paparazzi and weights nearly 2KG! I use mine for motor racing and air displays but never wonder around a town or walk along the seafront with it. Mirrors on the other hand love the seafront! The light, the out of focus doughnuts on the sea and objects that are far away are all good for the mirrors!

While only 400mm at maximum focal length I thought I’d try it with a 1.4x teleconverter giving 560mm focal length. I took the same subjects withs the Sigma 600mm and Zeiss 500mm at Shoreham harbour and then up sampled the results as a comparison. I wanted to know if it is really worth having the extra reach of the 600mm lens for distant subjects.  I was shot from Position 1 ( see plan view above) and pointed towards the gravel machine.

There was a ship at Shoreham Harbour when I took these so took a shots of the bridge. I wondered if we could see the time on the ships clock inside the cabin with our long lenses?

iphone-image
Position 1 Ship at Shoreham Harbour (iPhone 6+)

 

Canon 100-400_1-4x-2233_ISO 800
Canon 100-400 LIS mk2 with 1.4x TC on 5Dmk3  (560mm)
Zeiss 500-2234_ISO 800
Zeiss 500mm f8 full Frame on Canon 5d mk3
Sigma 600-8269_ISO 1600
Sigma 600mm full frame on Canon 5D mk3

 

All three lenses enabled me to see the time on the clock when zoomed into 100%. As you can see the Canon zoom/TC combination is slightly sharper and delivers more contrast than the Zeiss with the Sigma much softer. Click for 100%

Canon 100-400_1-4x-2233_ISO 800
Canon 100-400 f4.5-5.6 (at f8) with 1.4x TC  – 5Dmk3

 

Zeiss 500-2234_ISO 800

Sigma 600-2242_ISO 800
Sigma 600mm f8 – Canon 5Dmk3

 

 

Q2. Is lens performance more closely matched when using a camera with a lower resolution sensor such as the Canon 5D 12MP on full frame.

The 12MP 5D is clearly less of a challenge for lenses than the 21MP 5Dk3 or the 50MP 5Ds/r. How much are the differences hidden by a lower resolution camera, and are mirror lenses of any point with higher resolution sensors?

 

Canon 100-400_1-4x-8263
Canon 100-400 LIS ll on Canon 5D (12MP)
Zeiss 500-8265
Zeiss 500 on Canon 5D (12MP)
Sigma 600-8269
Sigma 600 on Canon 5D

All three images look pretty good but interestingly I slightly preferred the image from the Zeiss to the Canon on this occasion, and the Sigma is still a distant third. Looked at in isolation though – most people viewing an image from the Sigma once sharpened and printed will probably be quite happy with it from this camera. The differences are still noticeable but smaller, as you’d expect.

 

As a matter of interest I decided to attempt to improve the Sigma image further with clarity, contrast, noise reduction and sharpening. Here is the result.It looks pretty good I think, closing the gap to the other too. This shows that with the right post processing the Sigma is capable of a good resulting image.

Sigma 600-8269-EditSharpened
Sigma 600mm f8 on 5D (12MP) Sharpened, Clarity and Noise reduction employed

 

Q3. Is it better to upsample the images from a shorter focal length?

Is better to use a 600mm lens or crop a smaller focal length mirror or conventional lens and upsample the result in photoshop or using other tools like Genuine Fractals or Sizefixer? i.e. 600mm Sigma or upsampled 500mm Zeiss or upsampled 400mm end of Canon 100-400 zoom?

I was going to upsize using something fancy like Sizefixer or Genuine Fractals, but actually I didn’t need to as the result was very clear. I just scaled up the images in Photoshop, aligning them with the reference image from the Sigma. Again the order is confirmed Canon > Zeiss > Sigma. Though the Zeiss runs the Canon close again. In fact with a little contrast the Zeiss images are comparable.

 

Canon-Upsized
Canon 560mm upsampled to match size of Sigma
Zeiss_upsampled
Zeiss 500 upsampled to match size of Sigma
Sigma
Sigma 600 as shot
Sigma2
Sigma 600 as shot
Zeiss2
Zeiss 500 Upsampled to match Sigma 600
Canon2
Canon 560mm upsampled to match Sigma 600mm

Stop a moment to consider how incredible these images are – we can clearly read the clock face! A combination of high res digital tech with lens from different eras.

I have shown that it is better to shoot with a lower focal length mirror or conventional refractive lens and upsample if the shorter focal length lens is much sharper. The Canon and Zeiss upsanpled images easily beat the 600mm Sigma in this test.

 

 

Q4. Is it better to shoot at a lower resolution in camera when using a mirror?

Some cameras, like my 5D mk3 has small Raw (sRAW) or medium RAW (mRAW) setting where the image is down-sampled in camera to produce a smaller, lower resolution image, perhaps more suitable for the capabilities of mirror lenses. However the advantage of saving the full size RAW is that you can carry out noise reduction on the full size image and then downsample to create a less noisy and sharper final image. Given the low cost of storage this probably makes sense.

From the tests with the 5D and 5Dk3 it was noticeable that there is more detail in the 21MP images. The almost identical images from the Zeiss and Canon suggest that they are capable of resolving more than the 12MP of the Canon 5D sensor (now 11 years old).

sRAW and mRAW are also not true RAW files – they are more like TIFF files in that they have the colour RGB data combined – or are “mosaiced” they are therefore not as flexible at recovering highlights or at white balance changes for example as a true RAW file.

sRAW is 5MP

mRaw is 10MP

Clearly shooting in these modes will not give a more detailed image, or an image that is as flexible in post processing as the 12MP image from the 5D so this would be a waste of time.

 

 

 

4.0 Overall Conclusions

I had fun playing with and testing these lenses. There is something quite extraordinary about a relatively small lens having such amazing reach.

The Zeiss 500mm f8 Mirotar enables the photographer to walk around unobtrusively with a small, light but very powerful lens, the Canon 100-400 does not. It enables shots that would otherwise be impossible and with practice (and ideally a bean bag support) can deliver sharp contrasty images. The following picture shows the resolution of the Zeiss. First the full frame and then the crop – Note the detail on the beer can. I shot this resting on the railing of Brighton Pier, looking down to the groyne.

Couple_Kronenborg_ ZeissCouple_Kronenborg_ Zeiss-2

The Zeiss is an extraordinary thing and highly recommended, if you can find one. The focus confirm adapter makes it viable to use handheld, but even this is certainly not a lens for fast moving subjects. Think of it as a long range land / seascape lens.

The Sigma 600mm f8 tested in isolation is capable of pleasing results and it is one of the best budget mirror lenses. These sell on ebay for around £200. The Sigma’s overall performance is much lower than the best of the 500 mirror lenses – the Zeiss Mirotar – but it is 1/5 of the cost. I’d consequently recommended the Sigma however (given the price) unreservedly for full frame users with 12MP sensors, for users of 21 -24 MP sensors it is worth a try. (In Canon’s case the 12MP sensor 5D has no live view.  Users with the latest 36-50MP cameras really should use a conventional telephoto lens for best results, as the sensor is resolving much more detail than the lens.  The low cost, light weight and(relative)  small size make it a useful option for drawing in distance scenes when travelling for example, as long as you can use a beanbag or tripod to steady it.

Required usage for the images is a factor here. If the images are to be shown on a screen or printed at smal sizes – up to A3 then the Sigma is recommended, but if you are expecting to crop / make bigger enlargements then the lack of sharpness and resolving power of the lens will be noticeable with modern higher resolution camera bodies. In some ways the size and weight advantage over the conventional lens are negated by the need to use a tripod. I haven’t seen a focus confirm adapter for this lens.

The Canon 100-400 f4.5-5.6L is an excellent lens by itself, with fast autofocus. Adding the teleconverter has little apparent effect on resolving power, but does slow the autofocus down considerably. I tried shooting motor sport in this configuration, but the autofocus was too slow. If you want a general purpose zoom of this length for Canon I would strongly recommend this over the mk1 version.

The Canon 100-400m mk ll however is my favourite telephoto if only appropriate on occasion, at sporting events for example where the rapid autofocus puts it head and shoulders above all the mirror lenses.

Alternatives to get this focal length.

If you want to get this sort of reach and can put up with having a big heavy lens a 300mm with 2x teleconverter could give better image quality but with considerable weight (and cost) and you may keep autofocus depending on your camera body and specific lens.

My previous tests however showed that the Zeiss Mirotar can take sharper images than the Mk1 Canon 100-400 with teleconverter. The Zeiss then remains the best Mirror Lens, the Sigma 600mm is now my second favourite.

Another thought. Mirrorless cameras have focussing aids like magnification or focus peaking. I’m therefore looking forward to trying the Zeiss on the Fuji Xpro2. The Sony A7 series would also be a good choice to exploit this lens.

I feel another test coming on…

5.0 Zeiss Mirotar Gallery

Appendix

A1. The Vivitar Solid Cat 600mm f8

The Vivitar Solid Cat is a rare lens, it was apparently made for Vivitar by the same company that built the Hubble Sapce telescope. I found an example at ClockTower Cameras in Brighton (Excellent shop for used film gear) in Canon fit (c£250), so I took a couple of shots with the 22MP 5D mk3. I shot handheld at 1600 ISO with a fast shutter speed and managed to get severals sharp(ish) shots. Certainly shots where camera shake wasn’t the issue. I used live view to focus and just looked through the lens. It was a very bright day which helped! This is quite a compact and lightweight lens so I think users will be tempted to handhold it, but as I previously said in part 1 of this article, a beanbag or tripod would be best.

The first thing you notice is just how low the contrast is. Straight out of camera and into Lightroom, shot in RAW. Compare this to the image taken with the Sigma.

Screen Shot 2015-09-07 at 13.07.13

This is the old American Express building in Brighton. This view is of the full frame. Vignetting is minor. The image not only lacks contrast but sharpness too, with the high ISO needed the whole image is very muddy.

Vivitar Solid CAT
Full Frame
Screen Shot 2015-09-07 at 13.07.42
100%

Using the Lightroom tools I increased sharpness, clarity, put on some noise reduction and increased sharpening with a mask and used the tone controls to give a much better histogram.

Screen Shot 2015-09-07 at 13.09.35

Vivitar Solid CAT
With Lightroom enhancements

This doesn’t look too bad – looking at a scaled down representation, but the 100% crop looks very poor.

100% after increasing contrast, sharpness and NR
100% after increasing contrast, sharpness and NR

Vivitar Solid CAT Conclusion

Unfortunately this is one of the worst Mirror lenses I have tried. In fact I think it may be the worse lens of any type I have tried. It is clearly no match for a modern digital sensor. I have however only tested one example  (I’ve only ever seen one) and so this may have been a bad copy.  I also didn’t use a tripod and may have been able to get more accurate focus, and a lower ISO, but frankly I don’t think it will make much difference. This lens  must be at least 25 years old, though there were no signs of mistreatment and the mirrors looked shiny.

There are less rare but still inexpensive choices available, that have, at least  in my hands delivered considerably better image quality such as the Tamron 500 f8 and Sigma 600mm f8. The best mirror lens so far tested is the considerably smaller Zeiss Mirotar 500mm f8.

So I’d give the Vivitar a miss.

A2. Vivitar 500mm F8

I responded to an ad for one of these low cost lenses for sale. The seller kindly allowed me to try the lens in their garden, which by astonishing coincidence looked over the silos, that I shot above, albeit from much further away.

I shot several images with different settings on a sturdy tripod with geared head. I used the Canon 5d mk3.

First the histogram. A fairly low contrast result – not as good as the Sigma 600.

Screen Shot 2016-02-10 at 23.56.17

The images were very poor. This is the overall scene unedited.

Vivitar 500mm f8

The crop of the silos unedited,

Vivitar 500mm f8-2

Turning up sharpening to 50 in Lightroom, adding Clarity, contrast, and levels renders this result. dreadful I’m afraid.

Vivitar 500mm f8-3

Clearly the Sigma is far better than the Vivitar – or more correctly the example of Sigma that I tried performs better than the example of Vivitar I tried, remember these lenses are quite old now. Given the low cost and good availability of the Sigma I’d say that it is worth a try. After all a conventional Canon 600mm lens costs £6k+.

Give Vivitar mirror lenses a miss however! Unfortunately this sort of experience gives mirror lenses a bad name, but as we have seen, some manufacturers went to a great deal of trouble to develop a quality product.

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6 thoughts on “Mirror! Mirror! -a guide to choosing and using Mirror lenses part two”

    1. Why not indeed! – I tried the Minolta Mirror on A Sony body with IS – and that worked handheld.

      I have tried the Samyang 500mm – it was dreadful I couldn’t et anything sharp with it.

  1. Thank you for these tests. Why not use a mirror on the Olympus OMD M5-II. I use it with a 300mm lens and I can take handhold shots of 1/10 sec. The stabilizer gives until 7 stops advantage. It also has focus peaking. I am going to test it myself. Did you test a Samyang/Rokinon mirror already. They have 300, 500 and 800mm mirrorlenses.

  2. Good tests! I use the Tamron 500mm f8 mirror lens (the second one – the first version did have a tripod bush) for moonshots and it is very good at these. I agree the cheap mirror lenses are mostly terrible. The Opteka 500mm f8 is very low in contrast and not that sharp, but it is pocketable and if you only want to experiment with donut art it is a cheap and lightweight.
    The best ‘pocket-sized’ mirror lens I have tried is the Kenko 400mm f8 which is extremely sharp, good in contrast, and quite small (though heavier than the Opteka), and is available new at a good price. With the smaller front element it seems to produce less distracting donuts. It is also possible to walk around with the lens on the camera around your neck without feeling silly!

    1. Oh, I meant to add that I use both on a Sony A58 (20Mp) with in-body stabilisation via a chipped adapter (one with the correct focal length data, not the cheap ones sold as ‘focus confirm’). It gives me around 4-5 stops anti-shake benefit and I would suggest this is essential if you want to use it in dull conditions or under artificial lights. I have taken lots of shots at 1/20 second and often had them all sharp.

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