My Old Russian 1000mm Mirror Lens Doubled

My old Russian mirror lens.

Russian MTO-11CA M42 mount mirror lens on Canon 5D mk II

Last year I purchased a 25 year old Russian mirror lens. It's a 1000mm f10 M42 screw mount lens, which is basically a telescope.

I've had a bit of fun with this lens, like photographing the Stroud Subscription Rooms and Ebley Mill from Rodborough Fort up Rodborough Hill.

Ebley Mill, Stroud, Gloucestershire from Rodborough Fort up Rodborough Hill. 

The Stroud Subscription Rooms from Rodborough Fort. 

I even took it on vacation with us and photographed a newly married couple with their photographer on the beach. Too bad their photographer was more interested in looking at the back of his camera than photographing them.

You're missing it! 

What this lens is really great at is photographing the moon. This is what I'd like to do more of.

Note: This image has been cropped a bit. 

Well on to today! Today I received in the post an old Tamron M42 screw mount 2x converter for my 1000mm mirror lens.

Old Tamron 2x converter, M42 screw mount. 

What a 2x converter does is double the focal length of your lens. So my 1000mm mirror lens will become a 2000mm mirror lens. Sadly it also reduces the maximum aperture as well, so this lens goes from a fixed f10 to something smaller like f20 (but don't quote me on that, I've not done the maths!) What this means is you'll need a lot of light to shoot in.

Luckily the moon has a lot of light! Sadly it's a cloudy evening. So before it got too dark I ran out and did a few quick test shots. These aren't great images but it will show you what this lens with 2x converter can do.

I took two sets of photos, both from our back garden and both using a 50mm lens (which is basically what you see with your own eyes), the 1000mm mirror lens and the 1000mm mirror with the 2x converter. All on my full frame 5D mk III. Here are the results.

First up, St. Lawrence Church steeple in Stroud from our garden in Rodborough.

50mm 

50mm Lens on a Canon 5D mk III full frame camera. St. Lawrence Church steeple in Stroud from Rodborough. (Centre of photo) 

1000mm

 1000mm mirror lens on a Canon 5D mk III full frame camera. Church steeple in Stroud from Rodborough. The steeple clearly visible now. And we can see the clock is wrong as it was closer to 4pm and getting dark here.

2000mm

And finally the 1000mm with the 2x converter making it a 2000mm lens. Same church steeple taken from the same spot in our back garden in Rodborough. 

I did this again with the Randwick TV transmitter across the valley. You really can't see it in this first photo, but it's there in the centre. 

50mm

 Then I swapped lenses and put on the 1000mm mirror lens.

1000mm

You can clearly see the transmitter now.

2000mm

And then again with the 2x converter. Not only can you see the transmitter well now but you can see that there is quite a strong vignette around the image as well. I suppose this is inevitable on a full frame camera and I doubt would be an issue on a cropped sensor. 

So in conclusion I'm a very happy camper and can't wait for the next clear night to shoot the moon! :-D

(Note: shooting with a long mirror lens often creates odd looking bokeh (out of focus areas) in the shapes of little doughnuts. This can be an issue with some photos, or it can be a creative part of the image.)