Luminous Landscape Forum

Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: jnmoore on May 12, 2013, 09:13:55 pm

Title: mirror long lenses not worth it?
Post by: jnmoore on May 12, 2013, 09:13:55 pm: I use a Fufi X-E1 (love it, previous MarkII owner) and looking for a long lens for bird/nature photography. The big guns Canon and Nikon are too expensive and heavy for my needs (and also very unbalanced on a mirrorless body) even though I know they are excellent. I'm looking at a Sigma 400mm mirror 5.6 minolta mount and also a Minolta Rokkor-X 500 F8 mirror lens. Both of these are much smaller than the big guns and suite my camera and back, and come in less than $500 used.

I know the contrast and overall sharpness will be less but perhaps these will still work well considering ability to correct CA and other problems in software. On the other hand the focus zone will be small and not great for moving subjects because no autofocus is available.

Should I just give up the idea of a lighter 300 or 400mm lens for my Fuji?

Any comments appreciated.
Title: Re: mirror long lenses not worth it?
Post by: Rob C on May 13, 2013, 03:45:55 am: Quote from: jnmoore on May 12, 2013, 09:13:55 pm
I use a Fufi X-E1 (love it, previous MarkII owner) and looking for a long lens for bird/nature photography. The big guns Canon and Nikon are too expensive and heavy for my needs (and also very unbalanced on a mirrorless body) even though I know they are excellent. I'm looking at a Sigma 400mm mirror 5.6 minolta mount and also a Minolta Rokkor-X 500 F8 mirror lens. Both of these are much smaller than the big guns and suite my camera and back, and come in less than $500 used.

I know the contrast and overall sharpness will be less but perhaps these will still work well considering ability to correct CA and other problems in software. On the other hand the focus zone will be small and not great for moving subjects because no autofocus is available.

Should I just give up the idea of a lighter 300 or 400mm lens for my Fuji?

Any comments appreciated.

Buy the Reflex. Have some fun. It's about pictures, not textbooks. Usually.

;-)

Rob C
Title: Re: mirror long lenses not worth it?
Post by: kers on May 13, 2013, 05:04:21 am: I agree with Rob,

The Mirror lens has some special qualities of its own...

No chromatic problems for one and a different sharp/unsharpness....

here a 500mm nikkor photo

(For sharpness a regular 400mm lens has even more detail)
Title: Re: mirror long lenses not worth it?
Post by: telyt on May 13, 2013, 11:48:26 am: Whether a lens is 'worth it' or not is highly subjective which means you're the best judge of its value to you.

What I liked about the mirror lens I had (500mm f/8 Reflex Nikkor):

Light weight & compact size for such a long focal length
good close-focus limit
relatively inexpensive (for a long focal length lens)

What I disliked:

the slow f/8 (nominal) aperture, which is in practice something slower because the secondary mirror blocks some of the light
no physically smaller apertures
the distracting out-of-focus highlights in the background

Keep in mind the compact physical size does not reduce the need for adequate support for sharp pictures.

Here's an example of a distracting highlights in the background:

(http://www.wildlightphoto.com/birds/picidae/acwo01.jpg)

Also note the vignetting caused by this particular model lens:

(http://www.wildlightphoto.com/birds/picidae/gifl00.jpg)
Title: Re: mirror long lenses not worth it?
Post by: Iluvmycam on May 13, 2013, 12:47:27 pm: I got 2 mirrors. I like em for the freaky bokeh. That is about it.
Title: Re: mirror long lenses not worth it?
Post by: Rob C on May 13, 2013, 12:48:52 pm: Quote from: wildlightphoto on May 13, 2013, 11:48:26 am
Whether a lens is 'worth it' or not is highly subjective which means you're the best judge of its value to you.

What I liked about the mirror lens I had (500mm f/8 Reflex Nikkor):

Light weight & compact size for such a long focal length
good close-focus limit
relatively inexpensive (for a long focal length lens)

What I disliked:

the slow f/8 (nominal) aperture, which is in practice something slower because the secondary mirror blocks some of the light
no physically smaller apertures
the distracting out-of-focus highlights in the background

Keep in mind the compact physical size does not reduce the need for adequate support for sharp pictures.

1. Here's an example of a distracting highlights in the background:

2 Also note the vignetting caused by this particular model lens:

You see? Points 1 & 2 are exactly what I find attractive about my Nikkor!

So, should manufacturers actually listen to the great unwashed with the pennies in their hot little hands? Unfortunately, for these lenses, Nikon did. Or so it seems. Shame they don't apply that philosophy to the tilter/shifters and give some of us what we really, really would like to have.

Rob C
Title: Re: mirror long lenses not worth it?
Post by: Rob C on May 13, 2013, 12:59:40 pm: Quote from: KLaban on May 13, 2013, 12:28:48 pm
Do you like doughnuts?

Speaking only for myself, the answer would have to be a resounding Yes!

My grandmother used to make wonderful ones and my wife had the art down too. Our Alsabrador would drool all over the tiles when she gathered that they were being made; I would swear that she understood the word. They sell commercial, pre-made ones here; I wouldn't offer them to a starving man: it would be a cynical act of cruelty. For a drowning man, however, a mercy: sink him at once and put him out of his misery if he tries to eat it, but save his life if he clings to it instead. Plastic tubes. The rubber doll version of the real deal.

Rob C
Title: Re: mirror long lenses not worth it?
Post by: Telecaster on May 13, 2013, 04:28:54 pm: I like mirror lenses myself. If they're good enough for the Hubble telescope (and pretty much all other big-aperture scopes)...

Tokina makes a fine & dandy 300mm mirror for the Micro-Four-Thirds system. I bought the lens with some trepidation after reading multiple lukewarm "reviews," but any concern disappeared after I actually took some photos with it. No problem resolving 4" tall streetsigns over half-a-mile away, and with good contrast too. The reviewers were either clueless or just did a copy & paste job.

-Dave-
Title: Now THESE are mirror lenses...
Post by: NancyP on May 13, 2013, 08:00:57 pm: after a fashion. You can attach a camera to these ginormous Dobsonian reflector telescopes. Note, these telescopes are modular and fit in the back of a SUV when disassembled.

Note that the bird photos are not of birds in flight. If your subject is in one place for a few seconds, the photos are really quite good, despite donut bokeh.
Title: Re: mirror long lenses not worth it?
Post by: shadowblade on May 13, 2013, 10:22:29 pm: The problem with mirror lenses is that there just aren't too many high-quality options available.

It's perfectly feasible to make a mirror lens with great image quality and smaller/lighter than regular lenses. By using something other than the Cassegrain setup, you can even get rid of the donut-shaped highlights. Trouble is, no-one's bothered to do it.

That said, some of the best lenses I've ever shot with were mirror lenses. They're called telescopes.
Title: Re: mirror long lenses not worth it?
Post by: jnmoore on May 14, 2013, 12:54:42 am: Thanks for all the good comments. Basically it seems like fun and worth trying especially considering the price (and size/weight).

I think the donuts can be dealt with on an otherwise good shot with some blur etc. in post. As long as the main subject is sharp and clear I should be able to deal with it. The trick, I guess, is to get the capture with the limitations of the reflex lens.

So lets give it a try...

John
Title: Re: mirror long lenses not worth it?
Post by: Rob C on May 14, 2013, 03:38:05 am: Quote from: jnmoore on May 14, 2013, 12:54:42 am
Thanks for all the good comments. Basically it seems like fun and worth trying especially considering the price (and size/weight).

I think the donuts can be dealt with on an otherwise good shot with some blur etc. in post. As long as the main subject is sharp and clear I should be able to deal with it. The trick, I guess, is to get the capture with the limitations of the reflex lens.

So lets give it a try...

John

Doughnuts.

Don't imagine that you automatically get them. Truth is, you have to choose specific lighting conditions and subjects for those beauties to come to your party.

If you dislike them, which some do, don't buy; if you enjoy their difference, don't hesitate - buy now whilst you still can. Problems? Can be easily damaged by hard bumps.

Rob C
Title: Longest consumer level mirror lens ;)
Post by: NancyP on May 14, 2013, 12:01:36 pm: http://www.faintfuzzies.com/Telescopes2.html
Take a look.
Dobsonian reflector with 48" diameter mirror, requires ladder to reach eyepiece/camera set-up.
"Faint Fuzzies" are distant galaxies and nebulae.
Title: Re: mirror long lenses not worth it?
Post by: telyt on May 14, 2013, 01:54:49 pm: Quote from: Rob C on May 14, 2013, 03:38:05 am

Doughnuts.

Don't imagine that you automatically get them. Truth is, you have to choose specific lighting conditions and subjects for those beauties to come to your party.

I found it was difficult to avoid the distracting effect even if not full doughnuts unless the background was a featureless sky which resulted in vignetting. A fun lens for some purposes, not for me though.
Title: Re: mirror long lenses not worth it?
Post by: joneil on May 14, 2013, 04:12:54 pm: Okay, lets put this in perspective. I have the 500mm F6.3 mirror lens from Samyang, which is sold under several different brand names, and including the T-ring adaptor, I have all of $200 invested in it. That is two hundred dollars, NOT two thousand. For the money invested, I love it.

A 500mm lens from Sigma is about $5,000 and the nikkor is about $8,000, or more. Mind you they are F4 lenses, not F6.3, so you loose the light. Sorry, don't know what the Canon goes for. But think about this - $200 vs $8,000, what does anybody expect for want such a vast price difference? Bottom line for me, for $200 - a lot of fun.

One last thought - I totally agree that the best "mirror lenses" are telescopes. But that is another topic altogether.
Title: Re: mirror long lenses not worth it?
Post by: telyt on May 14, 2013, 10:47:31 pm: Quote from: joneil on May 14, 2013, 04:12:54 pm
Okay, lets put this in perspective... Bottom line for me, for $200 - a lot of fun.

I agree, no question. I also have a $200 400mm lens and I don't expect APO-Telyt performance from it. As long as expectations are commensurate with the cost they can be a great value and lots of fun.
Title: Re: mirror long lenses not worth it?
Post by: telyt on May 17, 2013, 11:08:04 am: Quote from: wildlightphoto on May 14, 2013, 10:47:31 pm
I also have a $200 400mm lens ... As long as expectations are commensurate with the cost they can be a great value and lots of fun.

Here are a few example photos made with my $200 400mm lens:

(http://wildlightphoto.com/birds/corvidae/ybma01.jpg)

(http://wildlightphoto.com/birds/hirundinidae/trsw00.jpg)

(http://wildlightphoto.com/birds/ardeidae/greg02.jpg)

(http://wildlightphoto.com/birds/ardeidae/caegre06.jpg)

It's a refractive lens, not a mirror lens so it doesn't have the mirror lens' optical signature and it has a diaphragm. I don't make big prints unless I've stopped the lens down to f/8 or so.

If inexpensive is the goal it's quite a good lens. If compact size is the goal, a mirror lens is a better bet.
Title: Re: mirror long lenses not worth it?
Post by: Fine_Art on May 17, 2013, 11:56:31 am: It depends on the FL. The longer the lens required, the more it IS worth it.

I would not want a 500-600mm mirror when very good refractor telescopes are available at 600mm cheap.
I do like my 1200 mirror (10"/ 254mm) when refractor scopes start climbing to $2-3K and photographic lenses are $10K.

BTW donuts can be a non-issue with focus stacking.
Title: Re: mirror long lenses not worth it?
Post by: Rob C on May 17, 2013, 03:09:51 pm: Nikkor 8/500mm Cat. on D700.

Shot this afternoon during the middle of a rainy, windy period.

The file tells me: 1/1000 sec. at ISO 1000. Obviously, the aperture is fixed at f8.

It's pretty much full-frame with just enough cropped off to straighten the horizon. Not a doughnut in sight, I'm afraid.

Rob C
Title: Re: mirror long lenses not worth it?
Post by: Telecaster on May 17, 2013, 03:36:06 pm: Quote from: wildlightphoto on May 17, 2013, 11:08:04 am
Here are a few example photos made with my $200 400mm lens:

It's a refractive lens, not a mirror lens so it doesn't have the mirror lens' optical signature and it has a diaphragm. I don't make big prints unless I've stopped the lens down to f/8 or so.

If inexpensive is the goal it's quite a good lens. If compact size is the goal, a mirror lens is a better bet.

Doug...good stuff! Is that the Leitz f/6.8? I owned one for awhile about 15 years ago. Very nice optics but I found it kinda unwieldy in use. It's the kind of lens you have to dedicate yourself to. I'm just too impatient and distractible. :)

-Dave-
Title: Re: mirror long lenses not worth it?
Post by: telyt on May 17, 2013, 04:09:34 pm: Quote from: Telecaster on May 17, 2013, 03:36:06 pm
Doug...good stuff! Is that the Leitz f/6.8?

It's the Novoflex T-Noflexar. The Leitz f/6.8 has better color saturation and a curved field. The T-Noflexar's not bad for its age; I bought it because my Leitz 560mm f/6.8 is the version made for Novoflex so adding the 400 to the kit is just the lens head - not a lot of extra bulk, weight or $$$.

EDIT: It's not just mirror lenses that have distinctive optical signatures. Simple refractive lenses like the T-Noflexar and the Leitz f/6.8 lenses have distinctive optical signatures too, and whether its objectionable or not depends on the nature of the image and the tastes of the viewer. The most common artifact of these lenses results from what I believe is spherochromatic abberation, which can be seen as magenta or green fringes, most clearly on out-of-focus points of light or other out-of-focus high-contrast edges. Note the grasses in the upper part of this photo made with the Leitz 560mm f/6.8 (this is an extreme crop):

(http://www.wildlightphoto.com/mammals/mustelidae/ltweas00.jpg)

The mega-$$$$ lenses shouldn't show these artifacts.
Title: Re: mirror long lenses not worth it?
Post by: lowep on May 18, 2013, 06:53:54 am: example photos made with my $200 400mm lens

great to see what can be done with a $200 lens in the right hands!!!