A Lens better than a TeleVue-85? (1 Viewer)

[wavering]

As you will see, I have recently posted a thread on the comparative merits of the TeleVue-85 and the Sigma 50-500mm:

http://www.birdforum.net/showthread.php?t=142365

The TeleVue-85 setup is clearly superior and subsequent tests have confirmed that.

My question is: how much would I have to spend to get a lens to fit on my CanonEOS1000D to get clearly superior results? The TeleVue-85 fails to read a car number plate at one kilometre (this is relevant as I like to be able to read names and IMO Numbers on ships anything up to 5 miles away). Not to mention the shear desire for perfection.

I am saying a lens rather than another scope as digiscoping is not as quick or handy as a camera plus lens.

Would the Canon 400/2.8 do the trick - I am guessing that light collection is as important as shear magnification but maybe I am wrong? I know this is a very heavy lens but it will be always on a tripod so no big deal!

I do take bird pics occasionally but they won't stand still for me to run tests ...

 

[RJM]

Don't know about Canon lenses, but I would think something like a 400mm F4 with a 1.4x TC would do it. A 300mm F2.8 w/2x TC probably could too.

cheers,
Rick

 

[Neil]

For those sort of distances I think you'd be better of with a bigger Televue , or maybe a Takahashi
http://takahashiamerica.com/
Neil

 

[Derry]

B&H current prices for Canon

500mm is $6,000

800mm is $11,000

http://www.bhphotovideo.com/bnh/con...&sku=542293&is=REG&si=rev#anchorToReadReviews

plus a top notch gimbal head for control,,

since you have the TV85 what are the different power eyepieces you have to verify the exact magnification you will need for that five mile reading of the ships,, would extablish a baseline so you know the exact X you will need,, even the Canon 800mm may not be adequate,??

would also try a 1.4 converter on the TV85 and see what you get,, will give you 840mm or right at 17X which will read a car license at half a mile in good air,, knowing the quality of glass used in the TV scopes I would expect it to meet or exceed Canons biggest glass for a lot less $$$, of course no auto focus or IS,,

I shoot a lot through my TV85 with an Oly E3 and find the live view works fine (need a very good tripod) or I normally use the viewfinder while focusiing with great results,, after a few hundred photos you get the feel for the focus,,

when you start talking a half mile to five miles for a photographed subject that is a lot of atmosphere to be looking through parallel to the earths surface,, as you have found it will be one of the most uncontrolled of your variables,,

let us know what you decide,,

Derry

 

[Paul Corfield]

Water and air temperature usually differ so the air at the surface can be quite turbulent and result in shimmering and mirage like effects in the photo. Once you go for long distances, atmospheric effects will always limit your end result rather than the gear you are using. Even with my cheap Skywatcher 80ED I can read the name and numbers on a jumbo jet at cruising altitude which is around 12km or 40,000 feet. On a bad day it is just a blur, just depends on the weather, air temperature etc.

Paul.

 

[wavering]

Thanks for the comments regarding possible lenses - I may try to rent one or two for a day and report back.

Concerning the air shimmering and haze, my view is 5 miles across the bay and about 15 miles to North Africa.

In the morning the view across the bay is surprisingly shimmer free but sometimes misty. Probably about 20% of the time it is totally clear and any amount of magnification would be usable. After a hot day (we have not really had one since October 2008) it shimmers. Bear in mind that the sea stays pretty cool so that probably limits the shimmer effect.

The best views to North Africa tend to be at the end of a clear day when the sun shines from the NorthWest onto the mountains. The very best shots I have of North Africa are really pretty pathetic eg see below:

This was actually taken yesterday (an exceptionally clear, cool sunny day) through the TV85 and EOS1000D with a time delay to stop camera shake. I have to say I am surprised at how bad this is ...

 

[Neil]

Thanks for the comments regarding possible lenses - I may try to rent one or two for a day and report back.

Concerning the air shimmering and haze, my view is 5 miles across the bay and about 15 miles to North Africa.

In the morning the view across the bay is surprisingly shimmer free but sometimes misty. Probably about 20% of the time it is totally clear and any amount of magnification would be usable. After a hot day (we have not really had one since October 2008) it shimmers. Bear in mind that the sea stays pretty cool so that probably limits the shimmer effect.

The best views to North Africa tend to be at the end of a clear day when the sun shines from the NorthWest onto the mountains. The very best shots I have of North Africa are really pretty pathetic eg see below:

This was actually taken yesterday (an exceptionally clear, cool sunny day) through the TV85 and EOS1000D with a time delay to stop camera shake. I have to say I am surprised at how bad this is ...

Do you have mirror lockup with your camera as this would help. Your photo is overexposure a at least 1 stop. I had a quick fiddle with it. Exposures are difficult at this sort of distance so would be worth bracketing and taking in RAW.
Have a look at the Radian eyepieces for longer distances. I have a 12mm which is good but you might need a 6 mm or 8 mm. They good ER so digiscoping shouldn't be a problem.
Neil.

 

[wavering]

Thanks, Neil. Well, I did say they were crap photos.

Actually, I was bracketing but the sun here is blinding and was right behind me and very low so I could see nothing on the screen until I got inside and hid in a cupboard. By the time I got out of the cupboard it was dark ("the dog ate my homework")

As for mirror lockup, I have just read an interesting article on that which suggests balancing a glass of water on top of the camera to see mirror shake in action. I will experiment further with mirror lockup once the camera dries out.

Actually, I am not using an eyepiece on the TV85, see:

http://www.thingysoft.com/myblog/2008_week030.asp#7

You can see the scene on the screen on the EOS1000D (try pressing SET - the man in the shop said you could not but you can!)

 

[Paul Corfield]

Here's an example I took with my Skywatcher 80ED and Canon 450D. Distance to the boat was around 150m and the background is probably about 1 mile away. This is an extreme heat haze caused by a few degrees difference in temperature between the sea and the air above it. You are trying to photograph much over much bigger distances so there will bound to be some atmospheric disturbances, no matter how small. When I'm taking photos of birds even at 40m the detail will be robbed with air temperatures of just 15°c. In the winter when the air is cold and stable the details at the same distance will be crystal clear. The tiniest of disturbance in the air will distort details.

Your camera has mirror lock up and it has Live View, as you found out by pressing 'SET', read the manual as you can magnify the image on the screen too. Live View also locks the mirror up so either of those would be worth a try and use a cable release as well to trigger the shutter when everything is perfectly still.

Paul.

 

[macshark]

For terrestrial shots, atmospheric effects usually limit the practical magnification that is possible. However, everything else being equal, the lens with the larger effective aperture (which is pretty much the diameter of the front element for super telephoto lenses) should resolve more detail. If you are not interested in the quality of the picture (e.g. contrast, color) but simply want to read text that is very far, the most economical option may be to use a reflector scope with a 200mm front element aperture, especially if you are also interested in astronomy.