Why so much noise and so little focus?

[richardb]

Hi,

I have recently bought a new Sigma 50 - 500 lens.

I enthusiastically shot a bunch of shots this weekend, but I have been blown

away at the amount of colour noise that I see in the photos, as well as what

appears to be a lack of focus.

 

I have been using a tripod.

 

Is this just because it is a fairly slow lens, is it poor light, or is it just

me?

 

Regards

[steve_levine]

Slow,long lenses always have certain caveats. In digital ,like in film using a high ISO will produce noise/grain.

 

 

 

Ironically many long slow lenses, are suited only for the brightest of sunny days. Lenses like 400 F5.6 or 500 F8 were the norm until a few years ago. With 400 or 800 films on a cloudy day, and a moving subject, you are out of luck with such a slow lens. This is why they make teles with big apertures. But you better have big pockets too.

 

 

 

By "lack of focus", I assume you mean the shallow depth of field, wide open at the longer end of the zoom? This is an unfortunate nature of the beast that you have to practice and learn to live with.

 

 

Have fun though, that sounds like a nice range for a zoom for wildlife/birds etc.

 

 

First thing I'd do is to test the lens at various focal lengths and F stops on a tripod. But shoot a brick wall or similar surface to check for sharp focus. You have to establish the lens isn't broken, and that's it's working correctly. Then practice "follow focusing" various moving things.

[richardb]

Thanks Steve,

I will do some testing like that as soon as I get a chance.

The lack of focus I was refering to is not so much DOF, but rather that the entire Image seems to be out of focus. I scanned over the entire image to see if there was perhaps a different area than intended in focus, but there was none.

 

Im still blown away at the lack of detail on things like plumage and eyes. It breaks my heart. And the lens got excellent reviews all over the web!

[frank uhlig]

10x zooms are know to be soft at all ends.

 

And 500 mm on a film camera is already long. (Try steadying a 10 x 50 set of binoculars!) With a - possible - crop factor on a DSLR (you do not specify your camera, sorry) good 750mm technique is hard to learn and master. (Again try to hold a 15 x 60 binocular and make out what it shows .. very hard to hand hold anyway, these long tele lengths) Maybe it is just your wobbly tripod or an insuffcient lens collar? Show some of the "bad" results, and the defects may become more obvious.

 

Live and learn!

[richardb]

Thanks Frank. I am using a Nikon D70s (Digital). I was wondering if it is camera shake. I have posted 3 examples of the problem in my portfolio under a folder called failures. I would appreciate any comments. They can all be viewed large to see the problem.

[photo_dark]

Are you using mirror lockup as well?

[richardb]

Hi, thanks Dave.

As I understand it the D70s only has mirror lockup for cleaning purposes and you cannot shoot using it.

[sandysocks]

In all three of your samples, the plane of focus falls behind your intended subject. The pine needles in the first shot show fine sharpness, but the cone is not in focus.

[jam_pasion]

At what aperture did you shoot those subjects at? The maximum aperture on the 50-500 at the long end is 6.3. If you shot those wide open it will tend to be soft - just one of the quirks of these supertele-zooms. If you did, then try f8 or f9 if light permits.

[wearyo]

Richard , The 50-500 is the lens that is always on my camera. I have no problems at all with it. I shoot it wide open mostly at 200-400 iso. I find it ever so slightly soft at 500 so if I think of it I back down to 480. I always use a rest of some sorts but Have gotten Good flight shots swinging it hand held. I only use the single area focus on it (hope I said that right)so it focuses on what I want it to. I have used it with the D70 and the D200 with equal success.You may have a bad one. Good Luck Bob

[greg s]

Yes, they do look back focused a bit. Also, it's worthwhile to list the shutter speed, aperture, etc in the Details.

 

Cool looking birds!

[tom_jenner1]

Hey Richard,

 

Where were those nature shots taken? The feeding shots are very cool. I love the napping shot.

 

-Tom

[richardb]

Thanks. I was pretty much shooting at f6.3, but willtry 9 when possible. Im also going to change to single area focus and give that a try.

 

The nature shots were taken in different parks here in S Africa, with my 300mm Nikkor lens.

[alan_birnbaum]

The type of tripod head might also make a difference. For the sort of nature shots most people do with this sort of lens, consider one of these:

 

http://www.jobu-design.com/catalog/item/2588354/2985535.htm

 

or the slightly more expensive, improved version:

 

http://www.jobu-design.com/catalog/item/2588354/4163794.htm

 

either one, of course, atop a GOOD tripod, that is tall enough such that you are not extending the center post.