[Lowell Goudge]

over the weekend, I had a chance to compare the performance of several long lens options and setups, with a preditcable but somewhat shy subject. A house wren.

the three photos that follow are done with my 3 long lens working solutions.
left to right
300mm F4 and 1.7x AF TC plus flash on *istD hand held (864 x 1296 pixels)
1000mm celestron C90 on *istD on tripod (1152 x 1728 pixels)
Sigma APO EX 70-200mm F2.8 plus 2x TC (also sigma) on K10D hand held (864 x 1296 pixels).

Note all images are cropped but not resized at all. All images were highest quality JPEGs out of the camera


in my view the sigma lens wins. I still have a problem with vibration on the C90 and the shot below was at 1/350 slower shots were not sharp.

Attached Images

 

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Last edited by Lowell Goudge; 09-27-2010 at 05:44 AM.

[hrishi]

Yes the sigma pic is better.. 300/4 + 1.7x is a little underexposed c90 would have looked better if the bird hadnt turned away at the last moment..Did the bird fly away n then returned to the spot? Sky weather looks much better during the sigma test..

what aperture did u use for the 300/4 + 1.7x TC combo?
Which is the optimum aperture for the 300/4?

[Lowell Goudge]

Yes the sigma pic is better

I agree

300/4 + 1.7x is a little underexposed c90 would have looked better if the bird hadnt turned away at the last moment..Did the bird fly away n then returned to the spot?

yes the bird kept returning here with food before going into its nest. Made it possible to set up the tripod, and wait.

Sky weather looks much better during the sigma test..

not sure but I think it was sunny vs cloudy

what aperture did u use for the 300/4 + 1.7x TC combo?
Which is the optimum aperture for the 300/4?

The 300/4 and 1.7x TC were shot using the TTL of the *istD. Set to either F8 or F11, I don't recall but these usually give good results.

One thing to keep in mind is that this is a bird about 4-5 inches long, shot from between 10 and 15 meters. When you consider the shot with the *istD (300 + 1.7x) and K10D (200 +2X) are the same pixel sizes, the shot n the K10D is a smaller actual image. The extra resolution of the K10D helps with this smaller percentage crop.

The shot with the C90 is a much larger image, but not as sharp due to shake. I am still struggling with this issue on the C90

[sandpipe]

The shot with the C90 is a much larger image, but not as sharp due to shake. I am still struggling with this issue on the C90

What do you think is causing the shake on the C90? Is the camera generating it or is it the scope/camera weight affecting the stability of the mount?

I'd love to see the results with the C90 after you eliminate the vibration problem.

If it's the mount what about using the shake reduction on the k10d even though it's on a tripod? I wonder if SR would be effective when the tripod is not perfectly stable even though I know SR is not supposed to be used when camera is mounted under normal situations?

[Lowell Goudge]

What do you think is causing the shake on the C90? Is the camera generating it or is it the scope/camera weight affecting the stability of the mount?

I'd love to see the results with the C90 after you eliminate the vibration problem.

If it's the mount what about using the shake reduction on the k10d even though it's on a tripod? I wonder if SR would be effective when the tripod is not perfectly stable even though I know SR is not supposed to be used when camera is mounted under normal situations?

It seems to be a combination of the ball head and the tripod mount on the telescope.

I use a long lens support from a tripod leg to the camera, and this removes some motion but there still seems to be too much. I am next going to look at the attachment of the mount to the telescope, as someone else commented this could be problematic.

Do not forget that the images are very small in proportion to the full frame, even of the *istD, at between 1/6 and 1/3 of the frame, and 1/10 of th eK10D frame.

[Ben_Edict]

If it's the mount what about using the shake reduction on the k10d even though it's on a tripod? I wonder if SR would be effective when the tripod is not perfectly stable even though I know SR is not supposed to be used when camera is mounted under normal situations?

No, that would not help. The combination of the tripod/head/head joint gives a completely different motion, than a handheld lens (mainly shake along the X/Y axis). The tripod combination will not shake along these defined exis but vibrate, which is omnidirectional. Ofcourse, that is only the theory, as the actual mechnical components of the tripod will influence certain directions. It is completely impossible vor SR to counterbalance this. That at least is my rough estimation.

Another problem with the C90 is its fixed aperture combined with an extremely shallow depth of field. If the little bird just moves his head, it will be out of focus, as the image demonstrates. At 10m distance on the K10 the dof is a mere 2.16cms... On the other hand a smaller aperture wouldn't be of much use, considering the viewfinder brightness and the onset of diffraction.

Ben

EDIT: I just wondered, whether we are talkig about the old (1000mm fl) or new C90 (1200mm fl)? Lowell wrote 1000mm, so that would give a slightly increased dof of 2.87cms. At 15m distance the dof would than be app. 7.5cms (3 inches), which would be enough for the little fellow on the branch.

[sandpipe]

Hand holding the 300mm x1.7 tc x 1.5 (aps-c factor) = 765mm lens with no SReduction! It's hard to tell just how sharp/blurry that first shot is because of the underexposure.
The C90 shot has the vibration problem so we don't know how sharp it could have been but if you solve the problem we might find out!
The final shot with the Sigma doesn't state the focal length you chose. Probably closer to the 200mm range than the 70mm range I presume? If at 200mm then that would be x2 for tc, and x 1.5 for aps-c factor = 600mm, handheld, with SR on k10d. Great shot!

Isn't the C90 1200mm focal length?

[Lowell Goudge]

Hand holding the 300mm x1.7 tc x 1.5 (aps-c factor) = 765mm lens with no SReduction! It's hard to tell just how sharp/blurry that first shot is because of the underexposure.
The C90 shot has the vibration problem so we don't know how sharp it could have been but if you solve the problem we might find out!
The final shot with the Sigma doesn't state the focal length you chose. Probably closer to the 200mm range than the 70mm range I presume? If at 200mm then that would be x2 for tc, and x 1.5 for aps-c factor = 600mm, handheld, with SR on k10d. Great shot!

Isn't the C90 1200mm focal length?

The C90 is an old scope, bought in about 1991, it is 1000 MM F11

Sigma shot was at 200mm plus the TC = 400 mm Bumped the ISO up to get shutter speed as SR is not fully compensated with the TC installed.

I was disappointed with the 300 F4 shot, I have taken better sharper shots with this setup, deliberately under expose and use flash to fill in. Not sure why it was not sharp.

[Lowell Goudge]

The C90 shot has the vibration problem so we don't know how sharp it could have been but if you solve the problem we might find out!

I might have the vibration sorted.

I took a look at the mount, and could not believe what I found.

My version is clad in protective rubber (it was an option)

The mount, which is about 2 inches square, is held on one side only by 2 screws (one loose), and is compressing the rubber coating.

I simply cut the protective coating away and now the mount is tight aggainst the hard body of the lens.

I will try again this weekend.

Long term, I may use epoxu between the mount and lens body to make it more solid, plus loktite on the screws.

[Ben_Edict]

I might have the vibration sorted.

I took a look at the mount, and could not believe what I found.

My version is clad in protective rubber (it was an option)

The mount, which is about 2 inches square, is held on one side only by 2 screws (one loose), and is compressing the rubber coating.

I simply cut the protective coating away and now the mount is tight aggainst the hard body of the lens.

I will try again this weekend.

Long term, I may use epoxu between the mount and lens body to make it more solid, plus loktite on the screws.

Well, at least that was an easy fix for you. On the Russian Maksutovs the tripod collar rotates on a simple ball bearing and cannot be clamped down at all. Though the Maksutovs are quite nice opticvally, the mechanics is more or less unusable… I just wonder, why so few users of the MTO complain about that contraption...

Ben

[Lowell Goudge]

Well, at least that was an easy fix for you. On the Russian Maksutovs the tripod collar rotates on a simple ball bearing and cannot be clamped down at all. Though the Maksutovs are quite nice opticvally, the mechanics is more or less unusable… I just wonder, why so few users of the MTO complain about that contraption...

Ben

You might want to try a long lens support onto the camera tripod mount to at least eliminate one degree of freedom.

[Blue]

The C90 is an old scope, bought in about 1991, it is 1000 MM F11

Sigma shot was at 200mm plus the TC = 400 mm Bumped the ISO up to get shutter speed as SR is not fully compensated with the TC installed.

I was disappointed with the 300 F4 shot, I have taken better sharper shots with this setup, deliberately under expose and use flash to fill in. Not sure why it was not sharp.

I just want to point out to people that there has been an evolution of some of celestrons scopes. The current rendition of the C90 is the C90 mak spotting scope that is weather proof at 1200mm and f13. They also have a c130 mak currently that is about 5.1 in diameter and 2000mm and f16. The current version of the C5 is 1250mm with an f10 and has the StarBright coating. The C5 spotting scope has been used by NASA on shuttle missions. Those are the three best production spotting scopes for photography use. They range from about $180-450 in price. The older classic version of these often sell for more than the new versions. Schmidt tellescope variations of the C5 have the motorized tracking capability.

Edit: B&H and Adorama have some decent prices on the new stuff.

[Ben_Edict]

I just want to point out to people that there has been an evolution of some of celestrons scopes. The current rendition of the C90 is the C90 mak spotting scope that is weather proof at 1200mm and f13. They also have a c130 mak currently that is about 5.1 in diameter and 2000mm and f16. The current version of the C5 is 1250mm with an f10 and has the StarBright coating. The C5 spotting scope has been used by NASA on shuttle missions. Those are the three best production spotting scopes for photography use.

I tend to be of differnt opinion. In my view (having the Pentax 75SDHF myself) the Pentax Apo spotting scopes, the Svaroswkys and ofcourse the Zeiss offerings are all better, qualitywise, than the Celestron. Not the least, because they have faster optics and are lens-based, not catadioptrics. Obviously they are not as cheap as the Celestrons.

Ben

[Ben_Edict]

You might want to try a long lens support onto the camera tripod mount to at least eliminate one degree of freedom.

You are right. That would help. But I think, I will simply get rid of the rotating collar and add a fixed tripod mount. There are several DIY projects on the net about that. I just use this lens so rarely these days, that this project will have to wait…

Ben

[Blue]

I tend to be of differnt opinion. In my view (having the Pentax 75SDHF myself) the Pentax Apo spotting scopes, the Svaroswkys and ofcourse the Zeiss offerings are all better, qualitywise, than the Celestron. Not the least, because they have faster optics and are lens-based, not catadioptrics. Obviously they are not as cheap as the Celestrons.

Ben

You took my statement way out of context. I was only discussing the Celestron C90 and C5 lineage of spotting scopes. I was also referring strictly to their Schmidt Cassegrain telescope, Maksutov Cassegrain Telescope lens. The three spotting scopes that I mentioned are infact developed from their Astro telescope line. I'm not very falmiar with Swarovski Optik, but the only scopes I've seen of theirs were straight potting scopes. But since you brought it up, I don't much care for Pentax spotting scopes since Bushnell serves the purpose better for standard spotting scopes. Zeiss is good but way over priced and not their focus. If I were to go with a sporting spotting scope, I'd probably go with the Bushnell Nature or Discoverer series.

Back to the point, The c90 mak is 90mm in diameter, the C130 is 127mm in diameter (5.1"0)and the C5 is 5" in diamter. There full blown Schmidt scopes range from 6", 8", 11" and all the way up to observatory scopes. It really irks me when people see one of those Five and Dime toys with celestron or meade on it and assume that is their real stuff.

Besides, if I were going to drop $2000 or more grand on a scope, it definately would be in the 11" range! If it were primarily for camera use, and had the money, I would go for long Pentax * glass.