Posted by Barry Southon on April 11, 2009 at 7:25 PM
Great Horned Owl with one of two fledglings.
Using car as hide shot through drivers window on bean bag and remote trigger release. 1dmk3 Canon 800mm + extender Very windy conditions prevailed. Nest located at least thirty feet above ground and was occupied by a pair of Red Tailed Hawks. The nest taken over by the GHO who don't take prisoners. They eat them. As I can illustrate with more photo's.
aghhhhh............ and just when I thought your mushy images were consigned to the past...... repeat after me
50mm on a FFDSLR = 1 x field of view (FOV)
800mm x 1.4tc x 1.3crop dslr = 1,456mm FOV.
shutter speed = 1/lens length FOV
1,456mm at 1/250s = blurred images,
1,456mm at at 1/1,500s = happy bunny
Looking another way; your set up you have the same FOV set up as a 30x telescope, what do nearly all digiscopers who hang a DSLR on the back of a telescope suffer from - mirror slap induced vibration
Get your shutter speed up or stop using the tc, it's killing your photography
Sorry mike your wrong! the idea is shutter speed = focal length, no matter what camera body you have attached, fov has nothing to do with it, for Canons explanation of this visit http://cpn.canon-europe.com/content/infobank/lenses/ef-s_and_field_of_view.do
Interesting image, shame about the oof branch that goes across their faces.
If you're using good technique there's absolutely no reason whatsoever why you shouldn't get bitingly sharp results with a shutter speed of 1/250 sec and much, much slower speeds, even with the large focal length you're using. I'd also have to disagree with the above statement that you need 1/500 second with that magnification. To illustrate the point and to offer quite an extreme example, I've not had an issue with mirror-slap or camera shake even when using ludicrously slow shutter speeds of up to a second with focal lengths including 700mm, 1000mm, and even 1400mm and that doesn't include the additional 1.6X crop factor. As I say, an extreme example but proves the point that you shouldn't have any issues with 1/250 sec.
If you're subject is stationary and you're using a rock solid support then you can often get away with ludicrously low shutter speeds even with a focal length that approaches, and exceeds, the one you're using.
What may have resulted in lost image quality could have been subject movement. You mention it was very windy, perhaps this was causing your subject to move in and out of focus, with maybe even the whole tree moving back and forth. If you was shooting in one shot mode this could have meant the subject moved in and out of the point of sharp focus.
Whilst cars are pretty solid, that's only if you're sitting very still.
Another factor is the atmospheric conditions. That's a lot of focal length you're using so the subject was obviously quite some distance away. The sky looks blue and the light quite bright so perhaps haze was an issue.
Is it full frame? If not, perhaps the crop has taken it's toll on the image quality.
The rule about shooting at a shutter speed equal to, or faster than the focal length you're using relates to shooting handheld and not when the lens is supported securely on a solid beanbag and using a cable release as an extra precaution.
Posted by Barry Southon on April 12, 2009 at 10:35 AM
Now this topic is generating some very interesting points. From a really selfish stand point just what I was trying to envoke.
This image and my previous Osprey posting were both taken from the same spot, within minutes of each other from my vehicle. The GHO some thirty feet above ground in a cotton wood tree swaying in a gusting wind. The nest was indeed moving my guess several inches if not more. Justin's point there is spot on.
Now the Osprey was perched on a power line pole no wind movement other than it's feathers.
This image was sharp as Mike mentioned.
I used so much glass in order to obtain a result which I have managed perhaps not in this image but in others.
Now one further point I see no merit in posting to my mind and eye my best results to be told how good I am. What I'm seeking is critique and advice on my failures. Thus I'm trying to understand why and where I'm going wrong.
To my great relief that's what I'm reading with this posting and I thank you one and all.
Pleased the info was helpful.
Now you've confirmed the wind was moving the subject a great deal just be sure to use AI Servo focusing mode instead of One Shot in situations such as this, assuming that you weren't already of course.
Posted by Barry Southon on April 12, 2009 at 11:05 AM
Woops another factor I missed out was the crop factor which I did in Lightroom this may well have caused the mush. Sorry I should have mentioned it in the initial post.
Discussion
6 repliesUsing car as hide shot through drivers window on bean bag and remote trigger release. 1dmk3 Canon 800mm + extender Very windy conditions prevailed. Nest located at least thirty feet above ground and was occupied by a pair of Red Tailed Hawks. The nest taken over by the GHO who don't take prisoners. They eat them. As I can illustrate with more photo's.
1/250 sec f/9.0 ISO 640 1120mm 800mm + 1.4x
Critique Advice Comments most welcome
Thanks for looking.
Barry
50mm on a FFDSLR = 1 x field of view (FOV)
800mm x 1.4tc x 1.3crop dslr = 1,456mm FOV.
shutter speed = 1/lens length FOV
1,456mm at 1/250s = blurred images,
1,456mm at at 1/1,500s = happy bunny
Looking another way; your set up you have the same FOV set up as a 30x telescope, what do nearly all digiscopers who hang a DSLR on the back of a telescope suffer from - mirror slap induced vibration
Get your shutter speed up or stop using the tc, it's killing your photography
Interesting image, shame about the oof branch that goes across their faces.
If you're subject is stationary and you're using a rock solid support then you can often get away with ludicrously low shutter speeds even with a focal length that approaches, and exceeds, the one you're using.
What may have resulted in lost image quality could have been subject movement. You mention it was very windy, perhaps this was causing your subject to move in and out of focus, with maybe even the whole tree moving back and forth. If you was shooting in one shot mode this could have meant the subject moved in and out of the point of sharp focus.
Whilst cars are pretty solid, that's only if you're sitting very still.
Another factor is the atmospheric conditions. That's a lot of focal length you're using so the subject was obviously quite some distance away. The sky looks blue and the light quite bright so perhaps haze was an issue.
Is it full frame? If not, perhaps the crop has taken it's toll on the image quality.
The rule about shooting at a shutter speed equal to, or faster than the focal length you're using relates to shooting handheld and not when the lens is supported securely on a solid beanbag and using a cable release as an extra precaution.
This image and my previous Osprey posting were both taken from the same spot, within minutes of each other from my vehicle. The GHO some thirty feet above ground in a cotton wood tree swaying in a gusting wind. The nest was indeed moving my guess several inches if not more. Justin's point there is spot on.
Now the Osprey was perched on a power line pole no wind movement other than it's feathers.
This image was sharp as Mike mentioned.
I used so much glass in order to obtain a result which I have managed perhaps not in this image but in others.
Now one further point I see no merit in posting to my mind and eye my best results to be told how good I am. What I'm seeking is critique and advice on my failures. Thus I'm trying to understand why and where I'm going wrong.
To my great relief that's what I'm reading with this posting and I thank you one and all.
Pleased the info was helpful.
Now you've confirmed the wind was moving the subject a great deal just be sure to use AI Servo focusing mode instead of One Shot in situations such as this, assuming that you weren't already of course.