Beginner Focusing Advice on long lenses

KingSaxlingham

KingSaxlingham

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Name
Benjamin
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Hey all!

I've recently bought a 2nd hand Sigma 150-500mm lens to do some shots of birds from a bit further away. However I'm having a bit of trouble getting good focus on smaller birds. I've set the Focus on the 'middle spot', and what seems to look great in the viewfinder often comes out out of focus.

I've attached two examples. One of a Dunnock, which I 'think' is because i used to lower shutter speed (it was a gloomy morning) and a Blue Tit, that just doesn't seem right.

Both taken with the full 500. Any good advice?

Thanks!

Dunnock (focus)

Dunnock (focus)


Blue Tit (focus)

Blue Tit (focus)

 
Welcome Benjamin.
The Sigma 150-500 is likely to struggle handheld in poor conditions, the Dunnock picture reflect that.
The Blue Tit is testing the focus as it is such a small part of the image and with so many distractions across and around it to make the focus struggle.
Better conditions where you can, get closer and up the shutter speed.
 
Almost guaranteed camera shake. Use shutter priority - start at around 1,000th second. Obviously, you'll need to up your ISO to compensate, so use auto-ISO if you have it.

Better light and a tripod is the only way to get better pictures though. :(
 
The Sigma is a shockingly good lens between 150-350, but performance tails away drastically above 400mm. At 500mm, the combination of spherical aberration and relatively slow maximum aperture can make it hard to tell what's out of focus, and what's just plain blurry.
The first two lessons I learnt about shooting long lenses were:
1. You initially underestimate how much anchorage you need: the only way I can get critically sharp images at this focal length is to strap the lens and body onto a dual support, on a heavy tripod, dug well in, ballasted, and hope it's not too windy.
2. You initially underestimate haze: 500mm slices through quite a stack of air. Clear conditions make a really big difference to sharpness. You can't get good shots at distance on a muggy day, when air quality is poor.
 
The third lesson I learnt was not to underestimate shutter slap. At some combinations of aperture and shutter speed, on some camera/lens combinations, you simply can't get sharp images because of internal vibration. Lock up the shutter, or use electronic shutter if possible for best results.
 
Thanks! Some really good tips there. I have started carrying my tripod with me now, which has certainly helped on the fast moving birds.

really appreciate that.
 
I have the same problem at 200mm on a non VR lens. Cannot imagine handheld at 500mm.

Good tips
 
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