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First Light
01-16-2006, 12:44 AM
Greetings,

If you're ever in the market for a legacy "catadioptric" or "mirror" lens for lunar photography, you might find these shots interesting. Here's a full shot of the moon as it appeared tonight (shrunk 50%):


http://fourthirdsphoto.com/components/com_simpleboard/uploaded/images/MoonX1.jpg

Here are three shots, each taken with different mirror lenses. Shown are 100% crops of the right side of the moon with a Sigma 600mm f8.0, Tamron SP 500mm f8.0 and Sigma 400 f5.6 lens.


http://fourthirdsphoto.com/components/com_simpleboard/uploaded/images/MoonX3.jpg

All shots were taken tonight with my E-1 and MF-1 OM adapter, a sturdy tripod, and an RM-CB1 cable remote. The Tamron produced the best results. It had the best sharpness and contrast. There's a new review of the Tamron 500mm (http://fourthirdsphoto.com/component/option,com_simpleboard/Itemid,48/func,view/id,6461/catid,22/) in the User Reviews of Legacy Lenses forum. Sigma reviews should appear soon as well.

craig
01-16-2006, 12:52 AM
Good going FL, These were about as good as mine when I did the same thing with the tamron lens.
now if we had a F4 500mm 4/3 mirror lens... That would be a sweet lens IMO.
T

First Light
01-16-2006, 01:20 AM
Yeah, a 4/3rds 500mm f4.0 mirror lens would be sweet—especially with AF (there's a Minolta AF mirror lens). However, I believe there is some sort of design limitation that prevents a mirror lens from having a large aperture. I seem to recall hearing that they get really soft with a large aperture. So I don't think that a catadioptric 500mm f4.0 would be practical.

There's a company in Russia that makes a 500mm f5.6 mirror lens and I looked into getting one. They don't make it with an OM mount so you'd have to adapt it via one of the other mount adapters. But the diameter of the lens body is too big to fit on the camera. It would hit the pentaprism overhang and hand grip.

jebir
01-16-2006, 01:42 AM
Hi FL,

Thanks for this demonstration. It clearly shows what I have been recommended from others. The Tamron SP mirror is one of the better out there and for the low price it goes for nowadays, It is a bargain lens.

Also, your post here definitely puts my plan to sell off my biggest lens - an MTO-11SA 'Russian Barrel' 1000mm f/10 mirror lens - on hold.

Here is why:
130
(Klick for larger image.)

The image is taken with my E-1 + the MTO-SA11 showing a 100% crop of approximately the same part of the moon as you show (limited by the max limitations for upload pics). I took it almost exactly two months ago so it shows about the same shadows as your pictures. It is an SHQ straight out of the camera, taken at 1/125 sec at ISO 200, sharpness and contrast both = 0.

As the Russian Barrel shows a great deal of detail that the Tamron SP will never be able to show even with a 2x TC (according to your test), I have now decided to keep it.

Cheers, Jens.

PS. Anecdote:
I bought this lens with broken focusing mechanics for $40 and took it apart fully, renovated the barrel, cleaned the optics, and re-lubricated the threads, put it all together, and made an OM-mount for it. Then, I tried to take several images of various distant objects and only about 1 out of 20 pictures or so came out sharp so I was disappointed and thought there was something more wrong with the lens and planned to sell it.
Then, I bought the KatzEye Optics Plus Hilux focusing screen and all by a sudden, 9 out of 10 pictures became sharply focused! This image was actually taken to test my new Katz Eye focusing screen but since I had already mentally decided that the lens was out of order, I didn't really pay much attention to the absolute image sharpness.

Thanks to you, I now know that it is a good lens. Thanks!

EDIT: Sorry, I originally mixed the numbers and letters in the name of this lens. The correct name is "MTO-11SA" using the latin alphabet. Quite often it is referred to as "MTO-11CA" but that is what is written on the lens with Cyrillic alphabet (where "C"= latin"S").

First Light
01-16-2006, 04:14 AM
Wow Jens, that's some shot. It's so big! I had the same experience with MF—my E-1 is much easier to use with MF lenses thanks to my KEO split-prism focusing screen.

I'd like to see a photo of your Russian lens sometime. I'm not familiar with a "Russian Barrel".

I tried a 1000mm f10 Meade Schmidt-Cassegrain lens 6 months ago and was very disappointed. It produced very soft pictures. Maybe I had a bad one because I thought Meade made good stuff.

Finally, I coupled the Tamron SP 2x teleconverter to the 500mm lens and took the following shot last night (1000mm f16):


http://fourthirdsphoto.com/components/com_simpleboard/uploaded/images/MoonX1b.jpg

As you can see, the SP 2x teleconverter makes the image way too soft. I think it would have been better to take the 500mm image and resample it in Photoshop rather than use the tele. That just makes the image from your Russian lens that much more interesting.

I'm generally satisfied with the Tamron lenses so far. They're definitely not Digital Zuiko's (and I wish they were) but they're useable. But I'm disappointed with the Sigma lenses. The build quality of the Sigmas is great—possibly better than the Tamrons—but they're just too soft when adapted to an E-1. It's a shame. And I was hoping they would be good. Oh well. This just underscores the importance of testing this stuff before taking it on an important shoot.

Bojan Volcansek
01-16-2006, 05:45 AM
Can you please tell me what were the shutter speeds for those photos? Is it possible that lack of sharpness is due to moon movement? Please notice that with such long lenses, angular movement of moon/stars is quite noticable!
I would suggest opening the lens (non mirror of course) to something between 5.6 and 8 (most usual sweet spot of the lens), but if the shutter speed are longer - I would rather open the lens then use longer shutter speeds.

Just a suggestion,
yours Bojan

Ombrafoto
01-16-2006, 05:53 AM
There\'s a fellow on DPReview that seems to have had some good luck shooting with a 400mm F5 Orion telescope. No moon shots yet, just a couple of bird ones, but look pretty good for a $200 scope.

http://forums.dpreview.com/forums/read.asp?forum=1022&message=16713601

Bojan Volcansek
01-16-2006, 06:07 AM
This is my shot from I think 2 winters ago:
208
(Click on picture for full size)
Iso: 100, shutter speed 1/6.
Tamron sp300mm F5.6 with Tamron SP2x tc eq. focal length 1200 (real 600mm). I think sharpness (or lack of it) is more due to too long exposure. When real winter finally arrives in Toronto, I\'ll try it again.

yours Bojan

ps. I think this is 100% crop but I\'m not 100% sure :)

Ombrafoto
01-16-2006, 06:27 AM
Full moons are always the hardest to shoot.
There is a surprising amount of reflected light .

I always foung a partial moon would give the clearest shots.

gunnerx
01-16-2006, 07:42 AM
I used my friend\'s Bausch and Lomb 800mm mirror lens in prime mode last night. I think the downside with the E300 is the viewfinder for these shots. It\'s not bright enough to focus properly. Here\'s a 100% crop of the image.

http://media.gunnerx.org/photos/web/P1155752c.jpg

Resized full frame shot with PP.

http://media.gunnerx.org/photos/web/P1155752.jpg (http://media.gunnerx.org/photos/web/P1155752.jpg)

jebir
01-16-2006, 07:48 AM
Bojan Volcansek wrote:

Is it possible that lack of sharpness is due to moon movement? Please notice that with such long lenses, angular movement of moon/stars is quite noticable!
Hi Bojan and everyone else interested in this subject.

Some numbers to consider:

The earth rotates with 15 arc-seconds* per second.
* One arc second is 1/3600 degrees

For super-telephoto**, the theoretical angle-of-view per pixel (AOV/pixel) for a given focal length (FL in mm) is:


1450/FL [arc-seconds/pixel] for the E-1
1140/FL [arc-seconds/pixel] for the E-3/500
** Here, super-telephoto is when the horizontal angle of view is smaller than about 6° (FL ~170 mm in Fourthirds)

Dividing this AOV/pixel by the rate of earth rotation gives us the time it takes for any point on the moon, imaged through our lens, to pass one pixel on the sensor. That can serve as a good estimate of the slowest possible exposure time that won't give motion blur. This becomes approximately (rounded to easily memorizable numbers) a rule-of-thumb:


100/FL [seconds] for the E-1
75/FL [seconds] for the E-3/500
So, your E-1 with a 600 mm lens should be operated with an exposure time shorter than 1/6:th sec. My conclusion is that the softness you see in your picture taken with 1/6:th should not be produced by the earths rotation. I bet it is the lens + TC combination.

Cheers, Jens.

PS. Just for the fun of it, based on my shot above that was taken at 1/125 sec at ISO 200 with f/10, I would guess that FL's exposure time was about the same (with the 500/8). That would be about 25 times faster than the 1/5:th sec. stipulated by the rule-of-thumb. No earth-motion blur there.

I'm curious to learn what it really was FL.

craig
01-16-2006, 09:23 AM
We also need to think of all the atmosphere out their, and pollution, I would imagine UV for that distance. So I think it would be part of lens combo, but heck we are also shooting a LONG ways.
T

Bojan Volcansek
01-16-2006, 09:48 AM
First thank you Jens for very nice explanation

tspore wrote:

We also need to think of all the atmosphere out their, and pollution, I would imagine UV for that distance. So I think it would be part of lens combo, but heck we are also shooting a LONG ways.
T

considering that, my shot was shot in north Toronto (so not really clean air) but on ONE hell of a lot cold evening (something like -12 or -15 as far as I remember - what i DO remember is the snow was very \"loud\" under the boots, and I was freezing (more the E1 :) )
, roughly around 9pm EST, so the air was rather good for shotting

Sorry for big photo, I\'m very busy at work right now and I didn\'t have time to find and resize photo :(

AnnF
01-16-2006, 10:00 AM
Thanks. Read it all. I want one of those, too!

First Light
01-16-2006, 06:34 PM
Bojan Volcansek wrote:

Can you please tell me what were the shutter speeds for those photos? ...
Hi Bojan,

I was using pretty fast shutter speeds to avoid the problems you mentioned. I checked the EXIF data of the shots I posted and here are the speeds that I used:

• Sigma 600mm f8.0 – 1/350 s
• Tamron SP 500mm f8.0 – 1/250 s
• Sigma 400mm f5.6 – 1/750 s
• Tamron SP 500mm f8.0 + SP 2x (=1000mm f16) – 1/90 s

Fortunately, the moon is a fairly bright object to shoot so I was able to lock the ISO on 100 for all of the shots (I wanted to keep noise to a minimum). I focused with the help of my custom KEO split-prism focusing screen and took multiple shots, refocusing in between, to make sure that I got the best possible focus.

In addition to using a sturdy tripod, I also used my E-1's "anti-shock" (mirror lock-up) mode set to 3 seconds and I used an RM-CB1 cable remote.

Bojan Volcansek
01-16-2006, 07:57 PM
That\'s plenty fast, to eliminate moon movement... So if the photo seems not sharp enough, we can almost be certain that it is due to the lens... Oh well...

I remember gorgeus moon shot someone posted on dpreview. After some time, the explanation was that it was shot by some NASA telescope :)

Yours Bojan

Pavel
02-07-2006, 06:23 AM
Thanks a lot to you folks! I hate you all. I read that post about the russian lenses a few week back and due to it have not been able to get astronomy out of my mind. This is going to cost me, so I think it would be decent if all of you chipped in for the price of a good telescope for me.

I've been doing a lot of reading on this stuff in the last little while. I am most curious about how that 500 f 5.6 would perform. What I have learned at some of the experienced here at the raleigh astronomy club and from a local shop is that the mounts on those lenses are asking for trouble. Supposedly the mount of the Nikon is better but still will give very poor results from vibration and movement. Fl's setup seems to be as good as can be to get around that but I wonder as well if we can be sure the lens is to fault for the shots or perhaps the wind or atmospheric haze. Supposedly if the stars are twinkling - it's not a good night for shooting them.

This is a whole new world to me. I looked through several telescopes this weekend ( my girls were are awe of the stars since - I love it ) and found that from moment to moment the picture would change due to light cloud cover and atmospheric turbulance. It seems like a discipline that requires much knowledge and some good setups. I was in particular impressed with the telescope that was pointed at the moon. The view through it changed as I mentioned due to our conditions but when it was good it was stellar (Pun)! Far better relief and clarity. Incidentally it was a newtonian 10" mead. Wow!

Now on my limited funds I would love to have a 500 f 5.6 so as to be usefull for my primary interests on land - I have a hard time picturing the 1000 f 11 being much use. Is it, Jens? Do you use it much for land stuff?

Anyone with knowledge of the 500 f 5.6? I wanted to spring for the Nikon 500 f 8 but held off in hopes that the russian 5.6 may be as good and the 5.6 welcome. The prices were the same.

Now I'm wondering if a telescope like the Maksutov's that can be used on terrestrial stuff may not be the best. If those lenses around 1000 need a tripod anyhow - why not do it with a telescope, right? the aperture is the same, the mount the most solid and for the starts and moon it has the tracking functions.
so any advice from the more experienced.
My photography interest has been up and down all my life. I'd get into it for two to four years and then take four to six off. It's been flagging for the last year or so. This may revitalize it a bit ... or perhaps it's time to change one hobby for another.
The amount of stuff to learn is overwhelming - I love it!

So I'm ready to accept donations - and I can forgive that this forum started it all! :D

gunnerx
02-07-2006, 11:48 AM
I currently have 2 telescopes on loan from my friend. I think I have mentioned this before. One is a newtonian reflector which is 500mm fl. The other is a Schmidt-Cassegrain 800mm fl. I think both of these would not be quite ideal for terrestrial objects. Well, they can be but with great difficulty. The reflector's image is upside down and the cassegrain is upside down plus mirrored. It's quite hard trying to get used to the movement at night.

Also, the images require a lot of sharpening and precise focusing. Otherwise the image would be quite soft. Also a large extremely steady tripod is definitely needed.

jebir
02-08-2006, 01:01 PM
Now on my limited funds I would love to have a 500 f 5.6 so as to be usefull for my primary interests on land - I have a hard time picturing the 1000 f 11 being much use. Is it, Jens? Do you use it much for land stuff?
Hi Pavel,

these lenses are used at "prime focus" so you will have no problem with mirrored or up-side-down views through your dSLR. I would definitely not recommend the 1000/10 if you intend to use it for terrestrial objects like birds. I have done a few bird shots with my 1000/10 but it is really not any alternative to the effort of reducing the distance to the critters. You can use it but you will lose a lot of flexibility because you will need a tripod with that f/10 unless you have a very very good high iso performance of your camera. Also, as with all mirror lenses, the contrast is somewhat lower than the refractors - and the bokeh...:blah: ).



Anyone with knowledge of the 500 f 5.6? I wanted to spring for the Nikon 500 f 8 but held off in hopes that the russian 5.6 may be as good and the 5.6 welcome. The prices were the same.
I have not tried the 500/5.6 but my friend who is a true 'lens-addict' says it is the sharpest of all mirror lenses.

Cheers, Jens.

First Light
02-08-2006, 05:23 PM
Hi Pavel,

Like you, I'm very interested in the Rubinar 500mm f5.6 lens and I'm waiting for Tony or Jens to get one to see if they get the 4/3rds mount right. I'm also sad to see that Jens has confirmed my earlier conclusion that it won't physically fit on an E-1 because of its large 120-130mm diameter close to the camera. That's what stopped me from buying one last year.

According to Jens, you may be able to extend the lens farther away from the camera body so it will fit but I'd want to be sure that it can focus far enough beyond infinity to make it possible to use like this. I haven't seen too many lenses that can.

Even if it can be adapted, those of us with E-1's won't be able to use our camera's hand grip any more because the lens will be in the way. We'll have to improvise and hold the camera differently. This may turn out to be a deal-breaker also.

Finally, after pointing a variety of lenses at the moon, my next goal is to acquire a motor-driven telescope mount—maybe even one of the computer-controlled ones. It's a pain to have to move and reacquire the moon or a star every couple of minutes due to the earths rotation. But I have to admit ignorance about them so I have to do some rearch. I'm wondering if a telescope mount can be modified to work with standard camera mounts and if this would provide adequate stability. If anyone reading this has already been down this road and can offer advice, please chime in.

marcof
02-09-2006, 12:01 AM
not intended as SPAM, but anyone interested in digital astrophotography should take a look at:
http://groups.yahoo.com/group/digital_astro

I started this group way, WAY back in 2001. In the meantime it has expanded to more than 10,000 members which contribute very actively to it. (I am personally not very active anymore in this area)
just take a look at the amazing images people create with relatively easy equipment!
There is a LOT to find in this group, and it is one of the best and friendliest groups on this subject around. It even made Sky&Telescopes a while back :)

tspore
02-09-2006, 12:24 AM
Wow that shot on the home page is amazing.
With the 2X crop that would turn a telescope into a far reaching tool.
Tony

gunnerx
02-09-2006, 06:11 AM
Thanks for the link Marco! I will definitely join the group as I need help on using my friend's German mount.