What about mirror lenses?
LoriKTM
Registered Users Posts: 44 Big grins
I'm talking about the 500mm mirror lenses that are for sale so cheaply. Granted, most are slow, but it seems like this technology would be great for a compact/lightweight telephoto lens. Easier on the back (and wallet) than a huge 500mm F/4.
Why is it that I don't hear much about the mirror lens? Anyone have experiences they'd like to share?
Why is it that I don't hear much about the mirror lens? Anyone have experiences they'd like to share?
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I suspect that the Tamron will be a much better lens overall but it will still have some of the typical problems of a mirror lens system. Common problems:
Odd "donut" bokeh both in foreground and background. This is caused by the secondary mirror interrupting the light path. Some folks like it but most people find it disturbing and distracting.
Slow effective aperture. Most mirror lenses are rated by their "calculated" aperture, rather than the "effective" aperture (which is usually considerably less).
Low resolution. While some of the mirror lenses have good resolution, most do not. "Solid" cat designs tend to be best and even they do not compete with a good refractor design.
Low contrast. Many inexpensive cat lenses use aluminum as the reflecting surface. The better and best use silver coated surfaces but they still post relatively low contrast. This mostly means using the lens in very bright light, but it tolerates hard lighting fairly well.
"Macro?" Many cat lenses are given a "macro" designation by their manufacturer, but most suffer at close focus distances. It's another case of abusing the "macro" term and I have never seen a 1:1 cat lens so at best they are just a "marketing macro" of 1:7 to 1:3 magnification ratio.
With all of these problems and issues it makes you wonder why someone, like me for instance, would bother?
As you said before, cat lenses are short and they are (generally) lightweight. With modern digital cameras, especially full-frame imagers, mirror lenses are once again finding some use. The full-frame imagers tend to do better with less resolution and the low-noise properties also benefit when you have to stretch the limited tones of a low-contrast lens.
Cat lenses also encourage the use of camera/tripod mounting as opposed to the lens mounting that many extremely long lenses use. Mounting the tripod to the camera instead of the lens, for a long focal length, generally reduces the effects of mirror slap, meaning that the cat lenses may show less mirror vibration, allowing slower shutter speeds without resorting to MLU (mirror lock up).
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I would think the older and much more expensive ones by Sigma, Tamron, and Nikon would give better results.
But don't expect much from a $100 supertelephoto lens.
I sure don't expect much for a $100 lens! But I just wonder if someone makes a "good" mirror lens for a few hundred more. I see cheapies for sale all the time, and figure someone must be buying them if they keep making them.
It seems as though sticking with some of the name brands (like Ziggy has) would be a better bet. I see mixed reviews overall, with some people saying you just have to "know how to manual focus" to get decent pictures. Others say don't even bother, and just buy a used older MF lens off of ebay. Interesting.
Here is a comparison of the Tamron vs Canon 500mm f4.5L
http://www.bobatkins.com/photography/tutorials/mirror.html
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Nikons third and newest 500mm Mirror Lens. The older lenses doesn't have the orange line. Many people on the internet claims that this is the one of if not the best 500/8 mirror lens. Technically it has one of the shortest minimum focus distances found in 500mm, which is 1,5 meters or just around 5 feet.
If you want this lens at eBay, you must be ready to pay around 400 Euros for this third version. The second version goes for about half the price. The first version could have a much higher price because it goes back to 1961 (vintage).
thanks !
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I'd be interested in seeing pics from it, especially in comparison to any other long lens you have.
I do plan to compare:
Vivitar 500mm, f8 cat
Tamron 500mm, f8 SP cat (55B)
Vivitar 500mm, f6.3 (refractor, manual focus)
Sigma 50-500mm, f4-f6.3 EX HSM (Bigma, not the DG)
I'll do the comparison first using a Canon 5D MKII body, later I'll test just the Tamron cat on a 40D as well.
The Vivitar cat is a "T" mount with a Pentax/universal/m42 screw adapter and the Tamron is an Adaptall II with an Adapatall II to Pentax/universal/m42 screw adapter. Both of those will be attached to the camera via an m42/EOS adapter with focus confirmation. They will both be used on a tripod attached to the camera.
The Vivitar refractor is already adapted to a Pentax/universal/m42 screw adapter and will also be mounted via the m42/EOS adapter. It will be attached to the tripod via the lens and its integral collar.
Only the Bigma is an autofocus lens in EOS mount. The Bigma has tested to be very nice on the 5D MKII body and I do believe that it is capable of professional results. (I do think that our BigAl has a sharper copy than I do.
BTW, I have tested the Vivitar refractor before:
http://www.dgrin.com/showpost.php?p=918969&postcount=6
http://www.dgrin.com/showthread.php?t=27214
http://www.dgrin.com/showpost.php?p=329591&postcount=21
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http://www.adaptall-2.com/lenses/55B.html
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[OT: thanks for kind words Ziggy
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Minor update, I was looking at the lens I just recieved and it is the "55BB" version which is the last version and (supposedly) slightly improved.
The proper link for a description of this lens is:
http://www.adaptall-2.com/lenses/55BB.html
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Tamron 500mm, f8 SP mirror (catadioptric, cat):
Vivitar 500mm, f8 cat:
Vivitar 500mm, f6.3 refractor @ f8:
Sigma 50-500mm, @ f8 and 500mm, manual focus:
Sigma 50-500mm, @ f8 and 500mm, autofocus:
Link to gallery with full sized images:
http://tinyurl.com/o5e69z
You can also click on the "description" above each image to get to the full-sized image. Be careful, these are big image files.
Notes: Body for the test was the Canon 5D MKII. All lenses except for the Sigma "Bigma" are manual focus, but I switdhed the Bigma to manual focus first to test it the same as the others. I used "Live View" and full digital zoom to manually focus. I shot 3 images and then close the sharpest of the 3 images to display for the test. The Sigma was, by far, the easiest to manually focus this way. I also repeated the Bigma tests with autofocus, just to see if there was a difference. I have to say that the the Bigma and the Canon 5D MKII autofocus nicely and better than the same lens even on the 1D MKII, which I cannot explain.
The 2 mirror lenses were mounted to the tripod via the camera. The 2 refractor lenses were mounted via their lens collar mount.
I would normally have selected a time-of-day so that the "arrow" sign, the target for these tests, would be sunlit. The morning was too cloudy so I had to wait 'till afternoon. Conditions were cloudy bright and if I detected a cloud obstructing the light I waited until it passed.
All of the lenses, except the Vivitar mirror lens, has a hood and I used it. I was shooting within the shadow of my house so I don't know what difference it might have made.
The Vivitar mirror lens was around 2/3rds slower than the Tamron mirror lens, even though they are both rated f8. The Sigma Bigma is not a true 500mm and I would guess around 460mm. The other lenses seem very close to the same length as each other.
"Donut" bokeh was not a terrible problem for either mirror lens in these conditions. The Tamron mirror was much easier to focus than the Vivitar mirror.
The Bigma and the Vivitar refractor are very similar in both sharpness and contrast at f8. The Tamron mirror lens is not too far behind in sharpness and the contrast is similar to the refractors. The Vivitar mirror is a sad fourth and almost unusable in terms of sharpness and contrast.
The Bigma would be my first choice and the HSM AF is fast and sure. This makes a very nice long lens for the FF Canon cameras if you have a tripod. Handheld it is a bit of a problem and you need to keep the shutter speeds up to manage it handheld.
The Tamron mirror is a pretty good substitute for a refractor if you are traveling light and need the length. It is much more manageable handheld but you still need a fairly fast shutter speed because of the focal length. It does require good light for most situations.
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Awesome review, thanks a lot!
You got quite a glass collection, my friend
The Tamron mirror just about holds it's own with the refractor lenses, and the bokeh doesn't look bad either! Good to see this technology is getting some improvements.
Hmm. Bigma or Tamron...decisions, decisions!
The Bigma is more of a "sure thing" useful lens with a very extensive zoom range and very competent AF. Collapsed it is heavy but not horribly large.
Mirror lenses will always be more conditional in their use. I am able to use an M42/EOS adapter with focus confirmation to assist in focusing the Tamron, so that lends to its usability.
The bokeh is a problem for many folks and the only real solution for mirror lens donut bokeh is in post-processing, using layers and masks to seperate the subject from the background and then treating the background to a "lens blur" or something like that. I hope to have some examples to show in the next few weeks.
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Thanks Nik. I drive very old vehicles and my food budget for this week is $24.
Cameras, lenses, lights, ... the expenses of photography keep me pretty broke.
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