[cooltouch]

Okay, I contacted my hosting service (GoDaddy), and got things straightened out. Here are a couple of examples of crops using a mirror lens. The lens was a Sigma 600mm mirror I bought new back in about 1984. These are film images. The first one is Fujichrome 100 and the second one is Kodachrome 64. There will be grain.

The first full image, resized for display here, an SCCA Sports 2000 class sport racer:



And a 100% crop of the above image:


This second image is actually a color Kodachrome slide, but the reflections off the water were so intense, they washed out all color:


And a 100% crop of the above image:


I was using a monopod with my Sigma 600 in the first shot and a stout tripod with the Sigma for the second shot. As you can see, even though I was shooting with film, detail is very good. I can only imagine what it would have looked like if I shot these images using my current 24.3mp digital.

So anyway, all I'm getting at is it is indeed possible to get good, usable crops from a quality mirror, such as that above Tamron, providing that proper technique is being followed. In fact, really, I'm restating the obvious, since there are several excellent images on the preceding page that have rendered outstanding crops.

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Last edited by cooltouch; 05-23-2019 at 08:09 AM.

[Skodadriver]

Sigma 600mm mirror, hand held. A little contrast adjustment.
The interesting thing is the spots on the camera sensor show as doughnuts (or polo mints).

[GUB]

Pentax K 400 - 600 zoom. Handheld

[goatsNdonkey]

Pentax K 400 - 600 zoom. Handheld

What delicate Spaghetti-O bokeh!

[Thagomizer]

Pentax K 400 - 600 zoom. Handheld

Love the poppy shot!

[Grippy]

Bought another K10 for a steal, it came with a Vivitar 500mm mirror, not something I would set out to buy, but hey it came with it, so I'll give it a whirl. It's a funny little thing, on the K10 I get the focus blip still, not on the K50, used the K50 for a test run with the dog as the weather is terrible and has been for the last week.
Minor contrast adjustments. It's a little soft for my liking, but it was handheld and Buster moves around a lot!

[goatsNdonkey]

Bought another K10 for a steal, it came with a Vivitar 500mm mirror, not something I would set out to buy, but hey it came with it, so I'll give it a whirl. It's a funny little thing, on the K10 I get the focus blip still, not on the K50, used the K50 for a test run with the dog as the weather is terrible and has been for the last week.
Minor contrast adjustments. It's a little soft for my liking, but it was handheld and Buster moves around a lot!

Who says a 500mm mirror isn't a portrait lens!

[steamloco76]

I haven’t taken my Tokina 500mm F8 Mirror lens out for over two months, so I figured it was time. A row of dahlia flowers along a farm drive caught my eye.

[MKohoutek]

This is an odd little lens, in that I have no clue how it works. Am liking the bokeh even though it is “undesirable”.

First shots...handheld using my K1. The exif says 300mm because I failed to change my settings.

[aslyfox]

fooling around with the K 3 and the Tamron Adaptall-2 SP 500mm f/8 Mirror (55BB)

hand held through the glass of the enclosure

SOOC

[Thagomizer]

This is an odd little lens, in that I have no clue how it works. Am liking the bokeh even though it is “undesirable”.

First shots...handheld using my K1. The exif says 300mm because I failed to change my settings.

The dragonfly shot is cool! I haven't really tried exploiting the "macro" abilities of my Tamron 55BB. This makes me want to try it out on smaller, closer subjects.

[aslyfox]

. . . The interesting thing is the spots on the camera sensor show as doughnuts (or polo mints).

This is an odd little lens, in that I have no clue how it works. Am liking the bokeh even though it is “undesirable”. ,. . .

what happens with mirror ( AKA catadioptric ) lenses:

" No Aperture: The Mirror Lens

The catadioptric or mirror lens—basically a reflector telescope—produces distinctive out-of-focus shapes popularly known as “doughnut bokeh.” Mirror lenses generally do not have adjustable diaphragm apertures. The distinctive shape of the bokeh comes from the design of the lens and the placement of the reflecting mirror in the center of the image. Light enters the optical tube, passes a small mirror, and strikes a concave mirror at the rear of the tube. The light is focused back toward the small mirror and reflected back through a hole in the concave mirror where the camera or eyepiece is mounted.

The result is bokeh with a bright edge and a relatively dark center. Some folks love this effect. Others despise it. Remember, bokeh quality is subjective . . . "

- Understanding Bokeh | B&H Explora

obviously not every photo taken with a " mirror " lens produces bokeh.

[ not my diagram ]

[goatsNdonkey]

what happens with mirror ( AKA catadioptric ) lenses:

" No Aperture: The Mirror Lens

The catadioptric or mirror lens—basically a reflector telescope—produces distinctive out-of-focus shapes popularly known as “doughnut bokeh.” Mirror lenses generally do not have adjustable diaphragm apertures. The distinctive shape of the bokeh comes from the design of the lens and the placement of the reflecting mirror in the center of the image. Light enters the optical tube, passes a small mirror, and strikes a concave mirror at the rear of the tube. The light is focused back toward the small mirror and reflected back through a hole in the concave mirror where the camera or eyepiece is mounted.

The result is bokeh with a bright edge and a relatively dark center. Some folks love this effect. Others despise it. Remember, bokeh quality is subjective . . . "

- Understanding Bokeh | B&H Explora

obviously not every photo taken with a " mirror " lens produces bokeh.

[ not my diagram ]

Nobody would buy donuts that look like mirror lens bokeh. Who want's a doughnut that is 80% hole? I call it Spaghetti-O bokeh. The popular canned pasta can have that kind of ring-to-hole ratio.

[aslyfox]

Nobody would buy donuts that look like mirror lens bokeh. Who want's a doughnut that is 80% hole? I call it Spaghetti-O bokeh. The popular canned pasta can have that kind of ring-to-hole ratio.

Hey, I never called them doughnuts, that is in the quote

[goatsNdonkey]

Hey, I never called them doughnuts, that is in the quote

I was only responding to seeing the term, which is almost universally used. I just think that it's an inaccurate analogy. I wasn't mad at anybody, certainly not another PFer.