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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

TS 107/700 triplet (1 Viewer)

Next round of tests. Lousy weather, so no birds ;) but at least a TV antenna about 60 meters away. Focus was on the bolt sticking up in the center. Look for the thread, and also check the CA on the aluminum rods.
First without my 1.6x TN
9615526160_117dd4f650_o.jpg

9615529562_c19bd93cfa_o.jpg

9612294311_5f2d363146_o.jpg
 
Still raining....
A BIRD!...
In the neighbors yard, about 30 meters away. 107/700 + 1.6x TN mounted on my Lensmaster RH-1 gimbal,
ISO 800, 1/30(!!) second.
9616215132_5992009334_o.jpg
 
Nice tests Dan,

Of course it is difficult to tell without having the full size pictures. However, here is what I see:

All photos seem quite good.

On the photos showing the complete antenna, both with and without TN, the 80 and 107 seem quite equivalent but the 90 looks better - however, it could be because the 80 is darker, hiding some of the definition. The 107 lacks contrast and definition and it is the one like the least - however again, it is is the lighter of the 3, which could be the cause.

Looking at the crops is a different story. The 90 is clearly the best, more definition, better constrast and less CA. The 107 seems to be the worse and the 80 is in the middle.

That's my opinion, for what it is worth.

Regards
Jules
 
Nice tests Dan,

Of course it is difficult to tell without having the full size pictures. However, here is what I see:

All photos seem quite good.

On the photos showing the complete antenna, both with and without TN, the 80 and 107 seem quite equivalent but the 90 looks better - however, it could be because the 80 is darker, hiding some of the definition. The 107 lacks contrast and definition and it is the one like the least - however again, it is is the lighter of the 3, which could be the cause.

Looking at the crops is a different story. The 90 is clearly the best, more definition, better constrast and less CA. The 107 seems to be the worse and the 80 is in the middle.

That's my opinion, for what it is worth.

Regards
Jules

strange how different we perceive things :) I actually found the 107 best and the 80 third
 
The crops are from the same files. They are not separate exports. I just went back and tried to balance the exposure on the crops. No other PP.
I see the 107/700 as being clearly ahead in resolution, which is to be expected. You can see a hint of thread on the bolt where there is just noise on the other two. The SW shows fringing on the silver rods where the 90/600 shows none.

I am very impressed with the 90/600, but the added reach of the 107/700 is nice. It is a beast, but I find the Lensmaster handles it well, although I doubt it would have without the ball bearings I installed on the tilt. It balances nicely and the weight seems to have real stabilizing advantages.
1120mm at 1/30 second with the gimbal free, not locked down. Don't know that I have been able to do that before.
But the 90/600 is really sweet! It measured at .986 Strehl!


I see now that a lot has gotten lost in the jpg conversion from the raw files. I will try and do the crops in Lightroom and then export them.
 
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I am leaning in the direction of a carbon TS 90/600, although I do also have an offer for a like new Stellarvue SV90T APO with a genuine Feathertouch 2.5" focuser on it. The 107 is nice, but it is just too much weight for only 100mm advantage in focal length.
 
The 107 is a bit on the heavy side, yes, specially if you're only going to have that scope, in my case my main scope will still be the TL 804, the 107 is going to be for those situations when I really can't get close enough.

But the 90 has little advantage over the ED80, is a bit better optically, but you'll pay three times more than the price of ED80. And you also don't get much more in light also, 90mm VS 80 is less than 1/3 of a stop.

Actually, this is me reasoning to myself a few years back. I also considered the 90 but I though it was to much money for so little gain. There's really nothing you can do with the 90 that you couldn't do with the ED80. JMHO ;)
 
I can get a TS 90/600 for roughly 1K€. This morning I did another comparison and I find the optical quality of the 90 enough better to make me seriously consider it.
9622378000_4ee0d548a5_h.jpg
90/600

9622374478_547eefeadb_h.jpg
80/600

The 107 is just too big and heavy to justify 100mm more focal length.
 
strange how different we perceive things :) I actually found the 107 best and the 80 third

Well, you are working from originals and I only have resized JPEGs to look at. I'm not surprised. You should get the one you like best, not the one others like...:t:

Regards
Jules
 
I can get a TS 90/600 for roughly 1K€. This morning I did another comparison and I find the optical quality of the 90 enough better to make me seriously consider it.
View attachment 460616
90/600

View attachment 460617
80/600

The 107 is just too big and heavy to justify 100mm more focal length.

There is indeed a difference looking at the feathers but it could very well be just differences in focusing.

IMO, other than price, construction, etc, there are 4 important factors to consider
  1. Weight
  2. Maximum f/
  3. Picture quality: resolution, CA, contrast, distorsion, etc.
  4. Reach

The first 3 are quite obvious but the last one is more complicated. There is a limit to it. We often see photos taken 1 km away but we all know it is not real day to day life. My SW80ED with barlow and crop factor reaches 2400mm: this is nice up to 100 meters in good conditions but after that, picture quality degrades very rapidly.

Also, how much weight are you willing to add to get that extra reach ? and, is that maximum reach usable in real life ?

Just my 2 cents...
J
 
I have repeated this test very carefully several times and it always comes out in favor of the 90. It is not a focus issue, but a doublet vs. triplet issue. There is just enough residual CA in the doublet to negatively effect the resolution and contrast, and since we are constantly having to do heavy crops, that is indeed a big factor. We can never seem to get enough feather detail in those distant LBJs!o:)

I am fine with 600mm and I am surprised how well the 90 works with my TN. I had noticed some iritating CA when using it with the SW, but I see none using it with the 90. Two kg and €700-800 lighter than the 107.

More speed would be good, but at what cost? I suppose I could get a 1990s Nikkor 600mm/f4, but it would cost me three times as much as a 90 and if the AF motor goes, I would be up a certain proverbial creek with no paddle. There are no spare parts/motors for those things. They simply can't be fixed. Talk about BIG! About the same weight as the 107. There are always going to be limitations, but f6.5 would do, especially as sensors and high ISO performance improve. In fact, when the light is really good, (not often) I even stop down to get more DoF.
 
I have repeated this test very carefully several times and it always comes out in favor of the 90. It is not a focus issue, but a doublet vs. triplet issue. There is just enough residual CA in the doublet to negatively effect the resolution and contrast, and since we are constantly having to do heavy crops, that is indeed a big factor. We can never seem to get enough feather detail in those distant LBJs!o:)

I am fine with 600mm and I am surprised how well the 90 works with my TN. I had noticed some iritating CA when using it with the SW, but I see none using it with the 90. Two kg and €700-800 lighter than the 107.

More speed would be good, but at what cost? I suppose I could get a 1990s Nikkor 600mm/f4, but it would cost me three times as much as a 90 and if the AF motor goes, I would be up a certain proverbial creek with no paddle. There are no spare parts/motors for those things. They simply can't be fixed. Talk about BIG! About the same weight as the 107. There are always going to be limitations, but f6.5 would do, especially as sensors and high ISO performance improve. In fact, when the light is really good, (not often) I even stop down to get more DoF.

If budget is an important factor, like it is for me, refractors are the way to go - as long as you are willing to live with manual focus. Water resistance is also a big difference, but I don't do birding in bad weather...

It looks like your decision is pretty well made. Good ! I wish you pleasure and success with it. I will look forward to see your photos.

Regards
Jules
 
Merci, Jules!
Still have to get it cleared with my finance minister....;) Might just wait a bit still with the new Olympus coming out in a couple of weeks.
 
"The new OM-1 could be a winner."

That is what I am afraid of:-C...

If it isn't, or if it is too expensive, I may just go with a D7100 and a 90/600. If it is, the 90/600 just might have to wait a while.
 
"The new OM-1 could be a winner."

That is what I am afraid of:-C...

If it isn't, or if it is too expensive, I may just go with a D7100 and a 90/600. If it is, the 90/600 just might have to wait a while.

I don't know who wrote that, but it is of concern for many of us...

"He, who has the most toys when he dies, wins." :t:
 
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