it's time for... a mirror lens thread :3

all taken with jintu 500mm f/6.3 lens (fixed aperture mirror telescope) mounted on canon eos m with @shuppy today

it was a lot of fun to take these, given a fixed aperture (and relatively slow but not that much) lens with a ridiculous zoom and fun optical errors and no image stabilizer

this will be 5 parts

pt 2

pt 3

pt 4

and final... uneven number huh

bonus: 3-parter at the local breakwater where i somehow never went before today, taken on 35mm f/2 with the same camera

pt 2 of that

uneven again lol

@q66 under which license are all of these really nice images?

@fun hm, none? i'm just posting them so people can look at them

i'm not going to sue you if you use them for something

@q66 none = all rights reserved

perhaps you want cc0?

@fun then it's cc-by-nc-nd because i don't want ai to use them

@q66 @fun CC-BY-SA (or even CC-BY) would probably be enough to prevent AI from legally being trained on them, since it can't really provide attribution and CC-BY-SA's copyleft would likely be incompatible with the licenses of other stuff the model is trained on. Although AI companies will probably not care and do it anyway regardless of the license.

@q66 @shuppy Very cool photos.

I perceive the unfocused parts as if I looked wrong and they weren't photos; I never considered bokeh rings (and possibly aberrations) to give such effects.

I'd not expect 500mm with no stabilization to be usable without much effort or more skilled handling than what I'd do.

@lukyan you can get away with unstablized 500mm (in my case the camera is aps-c, so it's really more like 800mm due to crop factor) if the light is good (and your camera has a good iso range), i was able to keep the shutter at less than 1/100th of a second most of the time which mostly shifts the trickiness to framing (due to sway) rather than sharp exposure, also f/6.3 is pretty fast for a mirror lens, normally they are f/8 or less which makes them even more demanding lighting-wise

the bokeh rings are a fun error, they are caused by the mirror lens having the center part so the whole thing is kinda donut shaped, you can achieve bokeh effects with standard lenses by placing an obstruction ovee your lens so the aperture ends up with the shape you like

this is the mirror lens attached to my camera for reference

@q66 That's encouraging.

I've seen photos of lenses of this type, but I haven't noticed before how small (or at least short) they can be.

@lukyan they are pretty large but compared to a refractive lens of the same zoom they are definitely smaller and lighter

but the main thing is that they are really cheap, equivalent refractive lenses will cost lots; i guess mainly because they are way simpler design-wise, it's really just two mirrors and a lens (meanwhile, a refractive telephoto lens will consist of *many* optical elements) and with that kind of simple structure it's free of eg chromatic aberration without the need for any correcting elements, but ofc they have their own errors and drawbacks...

@q66 I feel the regular telephoto lens prices (using Fujifilm X, also APS-C, but not at so large focal lengths) and know of optical element counts in their product pages. Price and simplicity can be very important advantages of mirror lenses.

@lukyan the specific lens i have actually has the t2 threaded mount so it can be put on almost any camera (it has 55mm flange which is quite a bit more than almost any dslr mount as well as any mirrorless mount, so the compatibility is large)

with fujifilm you get slightly less zoom, the crop for fujifilm aps-c is 1.52x as opposed to canon 1.6x so you will get around 760mm equivalent...