bmattock
Veteran
This is a lens that is seldom seen today, it seems history has passed it by. However, it once had quite a following, as it offered a long focal length (typically 500mm, sometimes 300mm or 600mm) and it was both lighter and shorter then typical prime lenses of that focal length, not to mention often cheaper.
The lens was unusual in that it was designed using a mirror (as the name 'mirror lens' implies). Here's a Wikipedia entry on this type of lens:
http://en.wikipedia.org/wiki/Catadioptric_system#Photographic_catadioptric_lenses
There are some limitations to lenses of this type. Among them, the most serious is probably the fixed f-stop. Generally, this was set at f/8. It could not be changed. Also, filtering had to be done after the optical components, not on the end of the lens as is normally done. Some catadioptric lenses offered small filters in the common (for B&W) colors that could be inserted into a chamber in back of the lens and in front of the lens mount. Another drawback was the odd and distinctive donut-shaped bokeh produced by such lenses. Some find it very objectionable, although some like it.
http://www.flickr.com/photos/monz/3773121132/
http://www.flickr.com/photos/glenn_calvin/3830469958/
Many companies made catadioptric lenses, and some of them were quite good optically, while some were quite bad. The average tended towards bad, in my opinion. They were usually intended to be low-cost lenses for those who wanted a long lens but could not afford the expensive top-end Canon L glass and so on. So quite often, corners were cut and cheap mirror lenses were not very good. They got a reputation for being generally bad because of this.
Vivitar made (actually sold under their brand name, they didn't 'make' anything) several Series 1 catadioptric lenses that were known to be quite good, and are considered 'cult classics' today. They are often known as 'solid cat' lenses because the space usually filled with air between the elements (making the mirror lenses quite light) are solid glass instead. These tend to go for quite a bit of money on eBay when they are listed.
However, there are many other mirror lenses that had good performance characteristics, and which have not 'caught on' as cult or classic lenses, so they can still be purchased cheaply, often new in the original boxes.
The mounting system most commonly used was the ubiquitous t-mount system, so a lens could be purchased and a mounting adapter added.
Tip: often such lenses are listed on eBay as being 'for' the lens mount that is currently on the lens, but if it is a true t-mount, one can purchase it cheaply, remove the lens mount, and substitute the lens mount actually desired. Sometimes t-mount lenses go cheaply on eBay because people do not realize that a t-mount lens for say, a Miranda camera can also be used on any other brand with an appropriate t-mount adapter.
A couple years ago, I purchased a Soligor C/D 500mm f/8 lens new in the box for next to nothing on eBay. It came with a Pentax P/K mount, which was actually what I needed anyway.
I haven't used it much. It is light, but I have found that using it on a dSLR (which effectively makes it act like a 750mm lens) is difficult. It has such a narrow field of view that it is hard to track moving objects - I tried it on geese and didn't have much luck. One definitely has to practice shooting with both eyes open, because once the subject slips out of the viewfinder, you can't easily find it again. Manual focus is iffy too, and it is very easy to blow the focus, since the lens is f/8 and the viewfinder can be fairly dark.
However, there are upsides. One, the 'donut' bokeh disappears when shooting against the sky. Two, the lens is quite light and short, so that's nice when doing a lot of panning and such. And three, the lens can be very sharp, if you manage to hit the focus just right.
I took mine to an air show yesterday. Got rained out, but I did manage to get a couple of halfway decent shots before leaving. Taken with the aforementioned Soligor mirror lens and my old trusty Pentax *ist DS (I should have put it on my K200D, but I just didn't get to it).
This may be one of my favorite shots ever. It's definitely in my top 100 'personal best' photos as of now:
Click on the image to see it full-size. The focus is bang-on (out of a stream of shots that were NOT in great focus) and the pilot is actually looking in my direction. I am posting it because it clearly illustrates that the catadioptric lens is quite capable of producing razor-sharp images, at times.
Is it worth adding to your SLR toolkit? Perhaps. The mirror lens has drawbacks, but it also has some distinct advantages. Consider it if you want a nice sharp long lens that is light-weight, short, and cheap. Keep in mind the disadvantages and decide if that's something you're willing to put up with.
The lens was unusual in that it was designed using a mirror (as the name 'mirror lens' implies). Here's a Wikipedia entry on this type of lens:
http://en.wikipedia.org/wiki/Catadioptric_system#Photographic_catadioptric_lenses
There are some limitations to lenses of this type. Among them, the most serious is probably the fixed f-stop. Generally, this was set at f/8. It could not be changed. Also, filtering had to be done after the optical components, not on the end of the lens as is normally done. Some catadioptric lenses offered small filters in the common (for B&W) colors that could be inserted into a chamber in back of the lens and in front of the lens mount. Another drawback was the odd and distinctive donut-shaped bokeh produced by such lenses. Some find it very objectionable, although some like it.
http://www.flickr.com/photos/monz/3773121132/
http://www.flickr.com/photos/glenn_calvin/3830469958/
Many companies made catadioptric lenses, and some of them were quite good optically, while some were quite bad. The average tended towards bad, in my opinion. They were usually intended to be low-cost lenses for those who wanted a long lens but could not afford the expensive top-end Canon L glass and so on. So quite often, corners were cut and cheap mirror lenses were not very good. They got a reputation for being generally bad because of this.
Vivitar made (actually sold under their brand name, they didn't 'make' anything) several Series 1 catadioptric lenses that were known to be quite good, and are considered 'cult classics' today. They are often known as 'solid cat' lenses because the space usually filled with air between the elements (making the mirror lenses quite light) are solid glass instead. These tend to go for quite a bit of money on eBay when they are listed.
However, there are many other mirror lenses that had good performance characteristics, and which have not 'caught on' as cult or classic lenses, so they can still be purchased cheaply, often new in the original boxes.
The mounting system most commonly used was the ubiquitous t-mount system, so a lens could be purchased and a mounting adapter added.
Tip: often such lenses are listed on eBay as being 'for' the lens mount that is currently on the lens, but if it is a true t-mount, one can purchase it cheaply, remove the lens mount, and substitute the lens mount actually desired. Sometimes t-mount lenses go cheaply on eBay because people do not realize that a t-mount lens for say, a Miranda camera can also be used on any other brand with an appropriate t-mount adapter.
A couple years ago, I purchased a Soligor C/D 500mm f/8 lens new in the box for next to nothing on eBay. It came with a Pentax P/K mount, which was actually what I needed anyway.
I haven't used it much. It is light, but I have found that using it on a dSLR (which effectively makes it act like a 750mm lens) is difficult. It has such a narrow field of view that it is hard to track moving objects - I tried it on geese and didn't have much luck. One definitely has to practice shooting with both eyes open, because once the subject slips out of the viewfinder, you can't easily find it again. Manual focus is iffy too, and it is very easy to blow the focus, since the lens is f/8 and the viewfinder can be fairly dark.
However, there are upsides. One, the 'donut' bokeh disappears when shooting against the sky. Two, the lens is quite light and short, so that's nice when doing a lot of panning and such. And three, the lens can be very sharp, if you manage to hit the focus just right.
I took mine to an air show yesterday. Got rained out, but I did manage to get a couple of halfway decent shots before leaving. Taken with the aforementioned Soligor mirror lens and my old trusty Pentax *ist DS (I should have put it on my K200D, but I just didn't get to it).
This may be one of my favorite shots ever. It's definitely in my top 100 'personal best' photos as of now:
Click on the image to see it full-size. The focus is bang-on (out of a stream of shots that were NOT in great focus) and the pilot is actually looking in my direction. I am posting it because it clearly illustrates that the catadioptric lens is quite capable of producing razor-sharp images, at times.
Is it worth adding to your SLR toolkit? Perhaps. The mirror lens has drawbacks, but it also has some distinct advantages. Consider it if you want a nice sharp long lens that is light-weight, short, and cheap. Keep in mind the disadvantages and decide if that's something you're willing to put up with.
