Went looking for Bighorn Sheep...

[Winston Mitchell]

...got lucky and found these instead.

Sony DSLR-A700, 1/90s f/11.0 at 400.0mm iso800

Sony DSLR-A700, 1/500s f/8.0 at 300.0mm iso800

Sony DSLR-A700, 1/350s f/8.0 at 360.0mm iso800

The images are geotagged. If you are browsing with IE7, a right-click on the image will get you a link to a map.

 

[Don Cohen]

Nice mountain goat shots, Winston. I saw a few of them when at Glacier National Park ("Goat Lick") , but I was extremely far away. The setting you show here looks identical to where I saw them many miles away. Shooting at 300 to 400 mm, you must have been fairly close to get this kind of detail.

The first shot shows 1/90s at f/11. Was this an oversight, or was there some reason for trying a relatively slow shutter speed and small aperture?

Thanks.

 

[Winston Mitchell]

Interesting comment about the "Goat Lick". Most of the eight goats I saw that day were busy licking rocks.

I was on one side of the road, they were on the other...very little cropping, just for aesthetic reasons.

About the first shot. I have a habit of taking " the shot I have" and then going for better ones. It turned out that of this series, the first one is the one that I picked.

All shots taken with with a bean bag.

 

[Don Cohen]

About the first shot. I have a habit of taking " the shot I have" and then going for better ones. It turned out that of this series, the first one is the one that I picked.

I often end up doing the same thing, which makes sense especially when you don't know how long your subject(s) will stay around for you to shoot. Take a few grab shots first, hoping for the best, and then tweak your settings if time allows.

As a general comment, to keep myself prepared for the best 'grab shot' possible, I shoot in Manual Exposure mode at least 95% of the time, and keep my camera set as close as possible to the lighting conditions where I anticipate my subject(s) being, so I'm at least in the ballpark when an opportunity presents itself. Light can change quickly, and so this doesn't always work, but it helps in the majority of circumstances.

 

[Winston Mitchell]

I too am usually better prepared but I thought I was done for the day. Camera was back in the zipped-up bag with a mounted 17-35.

My usual setup when looking for wildlife is a mounted 100-400mm, Auto ISO (200-800), Aperture Priority (f/8).

 

[Don Cohen]

My usual setup when looking for wildlife is a mounted 100-400mm, Auto ISO (200-800), Aperture Priority (f/8).

I'm curious about how exactly the Auto ISO works on your Sony, specifically with regard to shutter speed. If you're on Aperture Priority, set to f/8, then that's what your camera will use. But there are obvioulsy many combinations of ISO and shutter speed that will give you the same exposure, so what determines which combination it will use?

I have long wanted an Auto ISO type function in my Canon DSLR, where I could manually set both the aperture and shutter speed, and allow the camera to set the ISO (which could be tweaked by EV Compensation, the same as with any automated exposure process). That would be a great way of shooting in situations where light is changing rapidly, or being prepared for a quick "grab shot" where the lighting can't be reasonably anticipated.

 

[Winston Mitchell]

Here's what I know.

I can set the low end if the range to 200 or 400. I can set the highend at 400, 800, or 1,600. I set it to operate between 200 and 800.

At a given focal length, it maintains a speed by varying the ISO.

I just tested it with all of the marked focal lengths on my lenses with the camera displaying half-stops. The numbers change a little when it displays third-stops

400mm 1/500
300mm 1/500
200mm 1/350
135mm 1/250
100mm 1/200
75mm 1/125
60mm 1/90
50mm 1/90
35mm 1/60
28mm 1/45
24mm 1/45
20mm 1/30
17mm 1/30
16mm 1/30
14mm 1/30
12mm 1/30
11mm 1/30

It seems as though 1/30 is a low as it goes. I get the same result with anti-shake on or off.

For me, a big change in success rate with flitting/flying birds.

Hope this helps.

 

[Don Cohen]

Very interesting, Winston. Thanks for the research.

Looks like what it's doing is reasonable, and based on the commonly used formula that in order to avoid a blurred image from camera shake, you need to use a shutter speed shorter than the reciprocal of the focal length. Shooting at 400mm you need less than 1/400 second, shooting at 50mm, you can avoid shake with 1/50 second, etc. The camera's algorithm seems to use this, going at least a little quicker than the reciprocal of the shutter speed.

It's not quite the same as the theoretical AutoISO mode that I described above, but I can see how this can definitely be useful in various circumstances.

Thanks!

 

[Winston Mitchell]

Rather than set the shutter speed, I would like to be able to shift the aperture/speed table up and down by a couple of stops in third-stop increments. One less thing to set that way.

BTW, the table I posted seems to be very close to the reciprocal of the focal length with an accounting for the crop factor.