TS optics TL APO 804, a small review. (1 Viewer)

After a few weeks using the TS optics TL APO 804, here’s some thoughts and samples on the scope.

It’s a small telescope and it’s size and form is about right for this use, the build quality is really nice and the focuser is very solid and smooth. The white shinny paint job is a pain though, it’s nice to look at but to go unnoticeable to birds is not a so good idea (not that astro scope manufacturers have birders in mind when making them), this thing can be seen miles away, camo of some kind is definitely applicable here, I’m probably going to put some custom camo vinyl around it in the near future.

Now for the most important part, optical quality. Sharpness is about the best I’ve ever seen in any lens, close or far it doesn’t matter, images are sharp, very sharp. CA is nearly absent, not only in the focused part of the image but the out of focus too. The SW ED80 although nearly CA free in the focused areas was not so much as this one in the out of focus parts. 1.4 or 2x TCs can be used with no reservations, as long as there’s enough light.

The down side, field flateness. Being a shorter scope field flatteness is an issue, for any given lens the shorter the focal lens more curvature it will have. So curvature is noticeable here, much more than the ED80. Will it bother the final image? Maybe some images, but for the most part I don’t think it will, unless you’ll be using this for brick wall shots. Birds aren’t flat, nor will they occupy the full frame of the image, so this wont be much of an issue in most cases.
That said I definitely miss the lesser curvature of the ED80.

Also, there’s a “solution” for curvature, a field flattener. I use a skywatcher field flattener, since I already owned one I tried it on the APO804. Optically, I really can’t see many defects introduced by the flattener, sharpness appears to be same with or without flattener and color temperature is very slightly changed to warmer. That said, although on a well focused shot I can’t see a difference in sharpness, in practice I have a hard time focusing the scope when the flattener is on, a real hard time. While I rarely miss a stationary shot without the flattener, with it a rarely get one that is really spot on.
I don’t know why this is happening but it’s happening, so for now I quit using the flattener. Maybe in the future I’ll get to try a different one to see if I can focus better with it.

So here’s a few samples with it, they were all done with the flattener on and the Kenko Pro300 1.4x:

http://www.smugmug.com/gallery/5227414_UV8y2#1165711193_2AvMw-O-LB

http://www.smugmug.com/gallery/5227414_UV8y2#1165709690_6ezVU-O-LB

http://www.smugmug.com/gallery/5227414_UV8y2#1165581963_9vDuk-O-LB

http://www.smugmug.com/gallery/5227414_UV8y2#1165582067_tUmnM-O-LB

http://www.smugmug.com/gallery/5227414_UV8y2#1165582097_q4TQK-O-LB

http://www.smugmug.com/gallery/5227414_UV8y2#1165582176_Y8tSx-O-LB

http://www.smugmug.com/gallery/5227414_UV8y2#1165581934_2iei7-O-LB

http://www.smugmug.com/gallery/5227414_UV8y2#1165581800_XHo9f-O-LB


This was one of the goals I had in mind when I replaced the ED80 with the TS scope, flight shots:

http://www.smugmug.com/gallery/5227414_UV8y2#1165581750_G29MU-O-LB

http://www.smugmug.com/gallery/5227414_UV8y2#1165581593_5iRVK-O-LB

Being a small scope with a much better balance, it’s centre of gravity is about at the right place, almost bellow the focuser. That makes it really easy to hand hold the scope at the tripod mount and focus with the index and thumb of the same hand. It’s also light enough at 2.5Kg so handholding is not really an issue. Plus and probably the most important aspect is that by being an F/6 scope makes it very reliable to use a dandelion chip and trap focus, that makes the keepers rate at flight shots much higher.


Here’s a 100% crop, ISO500 1/500, with the kenko Pro300 1.4x and the flattener.
http://fernandobatista.smugmug.com/photos/1166341527_xSnnw-O.jpg

I don’t really consider this very sharp, but like I said it was done with the flattener on and I don’t think it’s perfectly focused.


I will be adding some more thoughts and pics in the future as I get to use it without the flattener, I already did a few this weekend and my keepers rate is much higher now.

Fernando,

Your album is really fantastic. Somehow I felt that the shots taken with the TL lacked a bit of contrast as compared to your other shots taken with the ED80. That might be due to the field flattener as you've mentioned which made focus difficult. Only further tests and practice may reveal other results. Eager to see further progress.

Just views from a novice, hope you don't mind.

tbc

Amazing review Fernando! hope to keep on reading about your jobs

Good review Fernando.

The small images are very good but the 100% crop with the flattener definitely shows something is lacking, in that particular image anyway.

Paul.

tbc said:

Fernando,
Your album is really fantastic. Somehow I felt that the shots taken with the TL lacked a bit of contrast as compared to your other shots taken with the ED80. That might be due to the field flattener as you've mentioned which made focus difficult. Only further tests and practice may reveal other results. Eager to see further progress.

Just views from a novice, hope you don't mind.

Click to expand...

Of course I don't mind, all views are welcome.

The lack of contrast is easily explainable. It's a cause from the light at the moment, in all these shots (except the sunrise plover and flying gulls), the weather was from light overcast to heavy overcast. Contrast was really low and shades almost nonexistent.
Using the same light and side-by-side contrast is the same as the ED80, in fact contrast is the area where all the three scopes (TL, ED70 and ED80) I used recently don't show a difference.
If you look at the last shots I have with the ED80 the difference will be big, since most of my latest ED80 shots are from August or September, even in the early morning the light is already very hard in these months. But frankly I far prefer this type of light than the harsh light from the summer, precisely for the softer look.

Remirath said:

Amazing review Fernando! hope to keep on reading about your jobs

Click to expand...

Thank you, Remirath
BTW congrats on your new scope, you first shots look very good.

Paul Corfield said:

The small images are very good but the 100% crop with the flattener definitely shows something is lacking, in that particular image anyway.

Click to expand...

All of them are like this at 100%. None have the sharpness I'm used too from the ED80. Of course the somewhat higher ISO (800 in most of them), and the general lack of contrast from the light can make things look worse. But something is definitely off.
I really can’t understand what’s the issue since on controlled tests shooting at home, even with TCs the flattener doesn’t appear to lose anything, but on the field I can’t have a really sharp image, the best I get is this.
What it seems to me is that only a very thin part within the DOF is really sharp. For example if for a given image I have a DOF of 30mm only 3 or 4mm of these are really sharp. I’m not sure but this is what I think it’s happening.

Anyway, after removing the flattener this weekend using the scope was much easier, focus point was far easier to see in the viewfinder and the sharpness I got was much better too.

"...What it seems to me is that only a very thin part within the DOF is really sharp. For example if for a given image I have a DOF of 30mm only 3 or 4mm of these are really sharp. I’m not sure but this is what I think it’s happenin..."

I'm no expert, but does it not have to do that one scope is f7.5 (larger dof) and the other f6 (thinner dof, compared) ?

another thought:
The differences you are experiencing - does it have to do with a different shooting style? (more without tripod etc?) Just a thought. Perhaps it's just not the scope itself, but little things around it.

Love your work.

Thanks for the input Cango. But no, what I'm saying is related to the TL APO804 only, I'm comparing using with and without the flattener.
The aperture in both situations (with or without flattener) is the same, F/6. But, with the flattener I seem to have less depth of the image sharp. Not less DOF, just less of the DOF is sharp.
Don't make much sense, I know, but it's what it looks like to me.

Orion Telescopes here in the states is offering a black triplet APO with similar specs to the TL APO 804. Does this look like the same scope or close: http://www.telescope.com/control/pr..._tube/~pcategory=telescopes/~product_id=09525

Rick

It is the same scope, only the tube is different.
Actually they're both made by Kunming Optics in China.
See here:
http://www.united-optics.com/Products/Telescope/Apochromatic_Telescope/80mm_F-6_APO.html

FernandoBatista said:

Plus, and probably the most important aspect, is that by being an F/6 scope, it makes it very reliable to use a dandelion chip and trap focus, that makes the keepers rate at flight shots much higher.

Click to expand...

I think i must be easy to please, because i think those shots with flatener all look terrific. You dont say why its harder to focus with a flatener mounted, as you dont go into detail , but the photos still look good to me

And does anyone really keep 100% crop photos for yourself or display ? Maybe for checking sharpness or whatever, but once you reduce the size, that very slight softness has disappeared.

The other thing, as per the quote of yours i posted, you use focus trap and it works because you say the scope is only f6, but can you still use focus trap when the 1.4x Kenko is mounted ?
The Kenko will be introducing 1 stop less of light, so effectively your metering is for for about f8.6/8.5/8.4 etc ? Is this not a problem with Kenko mounted ? What about the 2x Kenko which means you are metering for an effective f11+ ?

Well, I have reduced versions for web display, but I keep all photos in full size as I shoot for prints mainly, and I think that’s what most of us do. I print many of my photos in A4 size, and sometimes much bigger, for that you need detail.
The other day I printed four 50cm side pics from the ED80 to put on display on a photo store, although any of these pics would look fine at that size it wouldn’t do as good as the ED80 did. At 50cm size you’ll be able to tell the difference between these and the shots I’ve made without the flattener with little problems.

Besides, that’s the point of using scopes for me, ultimate sharpness. I never had any photo lens that could get close to these things for sharpness. But if I can’t focus correctly, what will it serve me for?

Yes, AF still works with the 1.4x tc, at least it works as well as the ED80 did, that is, the AF central point works in good to average light, but it fails on some weaker lights. With the 2X TC I’d need a very strong light and contrasty subject for trap focus to work. This is with my current body, a D90, with a D7000 or D300 it would work much better even in the off centre AF points.
That’s the point of having a 480mm F/6 for me, a bit more versatility, I have to get closer to the birds but I have more options. I can have what the ED80 had with the 1.4xTC or a shorter easier to handle lens when it’s needed (BIFs, better isolation, etc). Or use TCs at will when I’m desperate for reach.

You make good points on the 100% crops. I dont sell stuff, so i guess i wasnt thinking about that side of it.

Your point about maybe trying a different flattener, perhaps this is the answer, but the price of flatteners seems to vary a bit

Some of them are $200 - thats a lot to spend i suppose, but if it gets you the quality you need, maybe not

Musoman said:

And does anyone really keep 100% crop photos for yourself or display ? Maybe for checking sharpness or whatever, but once you reduce the size, that very slight softness has disappeared.

Click to expand...

To my eye the 100% crop wasn't showing a great deal of softness. To me any issues or degradation with the image were all optically induced.

Paul.

I suppose then, it could be the quality of the flattener, and when, or if, Fernando tries a better quality one, will maybe expose the culprit as the SW flattener

The problem would be finding a better quality flattener, the SW is cheap, but is the same flattener that WO sells for their 88. And WO sells it by twice the SW value.
The other alternatives are the AstroTech or the TS, I wouldn't mind spend 200€ on the TS if I knew it would work fine, but without trying I'm not going for another one.

Also what I don't get is that this happens with this scope, but never happened with the ED70 witch was what I bought the flattener for. On the ED70 I always focused fine with it, no difference at all. Maybe the TL804 and the SW flattener just don't "communicate" so well with each other.
On the other hand the curvature correction on the TL804 is much better than the ED70, there was still a good bit of curvature on the ED70 even with the flattener.

Fernando,

Just another couple of points that may be relevant to throw into the pot.!

Firstly, from my meagre knowledge of astro use, most of these flatteners are optimised for use at infinity/the stars, and therefore is it possible that you, when using for an image of a bird at 30 metres, are not getting the benefit of the design (for use at infinity) and possibly introducing more distortion than you are actually getting back in field flattening?

Secondly, is it possible that actually, the inherent curvature of field in the scope, is not something important enough, and is not bad enough to warrant a field flattener, when photographing elements in wild nature, where the main object in the scene possibly only takes up a third of the photograph. This is as opposed to images of the stars where all is exactly on one plane and necessitates the flattener to bring those stars on the edge of the field into focus.

Last thought just occured to me.......The curvature of field of a scope may even be of benefit in terrestial use, ( if it curves the correct way ) so that the front of the bird may be in focus and then the plane of focus could bend away, helping to bring surroundings into focus as well. !

Well, maybe. That though actually crossed my mind, the tests I’ve done at home are all at >20m, some at 60 or more meters, since I’m shooting from my window and there’s nothing closer than that distance. And all the shots I’ve done in the field are well bellow that, about 10m maximum. So that may be an issue. That said, I never noticed it on the ED70.

Agree, curvature maybe an advantage or not for this use, birds are not flat nor will they occupy the full frame. So in some situations it may actually be an advantage, for example, if a bird it’s on one of the thirds of the frame with it’s back for me and looking at me from the centre side of the frame, that will be an advantage as the curvature will follow the birds body. But in other cases it may become an issue, if a bird is parallel to the sensor, curvature may prevent from having the full bird in focus. I don’t think the curvature of the TL804 is bad enough that will be an issue there, but the ED70 was, all the turnstone shots I’ve done with it suffer from that, the head and body is in focus but the tail is off.
Another bad situation is a bird standing on a parallel branch, the bird may be in focus but the branch will show both ends out of focus, with a parallel branch that would appear evident in big prints and a it would look a bit weird.

I guess I’ll make my mind if this is a serious problem or not as I’ll use it more, I only used it this weekend without flattener and it didn’t bother me so much, so we’ll see in the future.

Can anyone explain what the point of a field flattener is for terrestrial use,I thought this was many for astronomical purposes,some superb photos on fernandos site though ,which version of the ED80 are people talking about, is it the Evostar or the equinox or doesnt it matter,might be tempted into getting one of these if photos as good as these are achievable

sparrowbirder said:

Can anyone explain what the point of a field flattener is for terrestrial use,I thought this was many for astronomical purposes,some superb photos on fernandos site though ,which version of the ED80 are people talking about, is it the Evostar or the equinox or doesnt it matter,might be tempted into getting one of these if photos as good as these are achievable

Click to expand...

One of the reasons Fernanado gave was a very good one. If you have a bird sat on a branch or a fence and you are photographing it square on you don't want both ends of the fence/branch going soft and out of focus.

The ED80 is the Evostar version.

Paul.

Fernando, if you haven't done already you could try varying the distance of the flattener from the camera sensor. I read about some users who tried them at the recommended distance but found on their particular scopes that altering it made for better images. Most flatteners have an optimal spacing to the film plane, not sure what the SW one is though

Paul.