Focal length

[Tom Rambaut]

This is a full frame out of the camera no adjustments/crop other than conversion image. lens 500mm + 1.4ext (700mm). I can not find the distance to subject info.

I was interested to know how this would look - size of bird in frame - if this was a straight 800mm or 800mm + 1.4 ext. This may not be possible but I wanted to get an idea of how it would look - this is a new location for me but this species does not come close. I did not keep any of my images of this species. May need a hide. If someone has the ability to crop the image to show me what it would look like as a full frame out of the camera image at 800 or 800 + 1.4 ext that would be great. Camera boby would be the 1D MK 4. The 800mm is a long way off if at all.


Thanks Tom

[Mike Milicia]

Assuming that your post was taken with a 500mm + 1.4x, here is the relative angle of view you would have gotten
if you had used a 800mm + 1.4x on the same camera body.
You are going from 700mm to 1120mm, so your focal length is increasing by a factor of 1.6.
Thus, the height and width of your subject will each be increased by a factor of 1.6.
This means that the area of the sensor taken up your subject will be increased by a factor of (1.6 x 1.6) = 2.56.

To get the resulting image, I opened your original image which was 1.95 in. x 2.93 in. at 350 ppi and then
did View->Rulers get a scale and then used the scale to crop to (1.95 / 1.6) x (2.93 / 1.6) = 1.22 in. x 1.83 in.

[Roger Clark]

Tom,
The 800 f/5.6 +1.4x will be f/8. Why not just get a 2x TC for your 500 (which will then be f/8 and 1000 mm). You can also (using version II TCs) stack 2x and 1.4x TCs with the 500 and still have IS, giving 1400 mm at f/11.2. That will work for slower moving subjects.

Roger

[Tom Rambaut]

Thanks Both.

Mike - That does make a big difference. These guys - Red-necked Avocets - would not come any closer that this. If I go back I may try some sort of hide. Thanks I would never have been able to work this out.

Roger - I do have a 2x TC (version 3). I did not pack it for some reason. I tried to stack a 1.4 TC (2) and 2x TC (3) the other day but found out that they are not compatable.

[Roger Clark]

Roger - I do have a 2x TC (version 3). I did not pack it for some reason. I tried to stack a 1.4 TC (2) and 2x TC (3) the other day but found out that they are not compatable.

Tom,
That's why I said version II TCs.

Roger

[John Chardine]

I have owned the Canon 1.4 and 2x TCs in version II and III forms and I have never been able to stack a 1.4 with a 2x without putting the 12mm tube in between. This is regardless of the version of the TC. Can you actually stack two 1.4x, two 2x or one of each, directly, without in intervening tube?

[Roger Clark]

I have owned the Canon 1.4 and 2x TCs in version II and III forms and I have never been able to stack a 1.4 with a 2x without putting the 12mm tube in between. This is regardless of the version of the TC. Can you actually stack two 1.4x, two 2x or one of each, directly, without in intervening tube?

Hi John,
I have the version II 1.4 and 2x TC and the version III 2x. I can stack the version II TCs in this order:

lens + 2x TC + 1.4x TC + camera.

Only one TC gets reported to the camera, so the camera thinks the system is lens +2x TC + camera. So with a 500 f/4, the camera thinks it is 1000 mm f/8 (and that is what is in the exif data), but it is really 1400 mm f/11.2. But the light meter reading is still accurate (because it just thinks the light level is lower). I've only rarely had problems with focus with 1D cameras.

I've got an awesome moon image from last month (my best so far with a telephoto); I'll try and get it up this weekend as an example.

At these focal lengths (above 1000 mm), stability and steady atmosphere is even more critical for good image quality.

Roger

[John Chardine]

Thanks Roger. You know what, I lied. Thinking about it, I never owned version II of the 2x tc, I went right to the III. I had a vII 1.4 and a vIII 2x and they would not go together. Now I have vIII of both and they won't go together directly either.

[Roger Clark]

Here is a link to my Moon image made with stacked 2+1.4x TCs (version II):
http://www.clarkvision.com/galleries...c-s-1024v.html
There is a link on the page to the full resolution image.

Roger

[Tom Rambaut]

Very cool Roger - I think I see footprints!

[John Chardine]

Yes Roger it is an impressively sharp image, full of detail.

[Marina Scarr]

I love my 2x TC with the 500L and use it quite often. I wouldn't go anywhere without it.