Michael thinks that it will be humongous and require a sherpa to carry around but I suspect it won't be any heavier or really larger (maybe somewhat longer) than the 600 f4 lens. Any educated guesses?

I'm pretty sure it will be quite similar to the FD mount 800

I'm just an enthusiast but I suspect that it'd be the fabled 800 DO, lightish and beautiful.

It's an Alaskan Portrait Lens.

It looks like it will be just about the same length and size as the 600 mm f/4. The 800 mm is at the back (with the 6m minimum focusing distance), the 600 mm is second from the back, and the 200 mm f/2 is up front in this high resolution 5436 x 4080 picture:

Canon 2008 Super Tele Group

Lenses are usually lighter if the maximum aperture is narrower, so one would expect the extra weight due to the longer focal length to be offset by a 1 stop slower lens, compared to the 600/4.

It's a pity the 40D does not have auto-focussing capability at f8. This 800mm lens plus 1.4x extender would give an effective reach in 35mm terms of 1800mm.

Hi!



Yes, that's a pity. Even more pity is that 1200mm f5.6 + 2x + 40D would give you 3840mm eqv but even less autofocus capability. But I guess that with such magnification you might be able to focus manually. Probably the hardest part would be to figure out what to shoot with these combos...

Cheers,
J

Not to mention the Nikkor 1200-1800 that is not an AF lens anyway.

cheers,
Bernard

I've got an 1800mm telescope (f12 Maksutov). It fills the frame on my 5D with the moon very nicely:)

http://farm2.static.flickr.com/1014/125721...964bfd463_o.jpg

Mike

Don't know about the availability or price of the Nikkor 1200-1800mm but last time I saw the Canon 1200mm listed it would have bought 15 pieces of 1Ds2/3-bodies.
More seriously, the new 800mm might be better served when married with a better camera than 40D. With the new 1Ds3 you would get aprox similar resolution compared to the 40D if cropped but with much better viewfinder and AF.

Cheers,
J

That's probably true. The 1Ds3 has the pixel density of a 20D and there's not much resolution difference between a 20D and the 40D; probably only noticeable on test charts.

Think of it as a 600 f4 with a built-in TC 1.4x and it sounds quite reasonable.

What is a pity, though is that the pro Canon bodies seem to need f2.8 to use all their AF sensors.

You must be referring to the cross-type behavior of some of the AF sensors.

All of the AF sensors of all 1-series bodies are horizontal-line sensitive at f/5.6, so AF can be used with the 800 f/5.6 for all sensors. However, only the central one will be vertical-line sensitive as well.

normally if you can afford a 800mm, you have another body than the 40D

I know of at least one person using a $6k tele and a 40D.

The 40D resolves the center of the lens better than any Canon DSLR except the 400D.

Hi!

Maybe 40D has better AF-performance than it's predecessors. 1-series bodies are light-years ahead of 10D and 20D when tracking moving subjects, flying birds for example.

Cheers,
J

You can't buy another stop of light. If I needed the range i'd put my long lens on a crop body.

Depends on the "crop" factor and difference in resolution. Eg: I could crop a 1ds3 down to the effective crop of my 1d3 at 1.3 and still have more resolution (if I recall crop on 22 mpx down to 1.3 is about 16 mpx, compared to the 10 for a 1d3.

Tim,

The 1DS3 is 21 megapixels - cropped to a true 1.3 that would give 14.7 mp. I think the 1d3 is actually a 1.27 crop (I'm not certain on this) and if so then cropping to that from the 1DS3 would give you about 15mp.

Lin

Spoken like someone who knows what they are talking about.

This lens, Canon 800mm F5.6, is now in the process of being released. I was fortunate enough to get to use (play with) one recently and have compiled a brief essay on the subject. This is by no means a definitive test or evaluation, but for those who are interested, you can check it out at my website www.kevindowie.com there's a link on the homepage. cheers KD

Agreed.

Firstly, this lens is reportedly 461mm long, and to be only about half as long as its focal length, it must have diverging rear elements (as all true telephoto designs do) giving almost 2x magnification of the image produced by the front elements. So it roughly resembles a 400/2.8 front part married to a 2xTC.
Likewise the 456mm long 600/4 must roughly resemble a 400/2.8 married to a 1.4x TC.


So how would using this 800/5.6 on a 35mm format DSLR of a given pixel size compare to
- using a 600/4 with 1.4x TC or a 400/2.8 with a 2x TC on the same body.
- using a 600/4 with no TC, with a sensor of about half the area and similar pixel count at half the ISO speed.


[Edit:] Adding a second smaller format body to your kit might be cheaper and lighter than adding this lens! Actually, this is my attitude to all long lenses slower than about f/4: I would rather use a shorter, brighter lens with either smaller pixels or a TC.

The 800mm Canon lens is smaller and lighter than the 600.Well .1 of an inch longer and 9.9 lbs vs 11 lbs for the 600 8 for the 800. Real close to the same length and 800 is smaller in Dia.

Roughly as expected for its 5% smaller effective diameter of 800mm/5.6=143mm vs 600mm/4=150mm, allowing front elements about 5% smaller in linear measure, 10% less in area.
The exact equivalent would be a 570 mm f/4 with 1.4xTC. What would that weigh? Probaly about the same as the 800/5.6.

Why: the weight of super telephotos seems roughly proportional to the square of effective aperture diameter, meaning proportional to estimated front element area. The weight difference between the 500/4 and 600/4 is 3.87kg vs 5.36kg, 40%, roughly matching this increase in estimated front element area.
The weight difference of 10% between the 800/5.6 and the 600/4 is also in proportion to estimated front element area.