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09-04-2014, 07:46 PM   #1
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Telephoto Zoom Underexposure

I purchased a New Sigma 120-400 telephoto zoom lens for my k-3 in order to take soccer photos.

I should mention that I have just moved from a k-10d to the k-3 and I am still getting used to the differences and that I have not used a 400mm telephoto lens before.

I tried it out shooting a late-afternoon / early-evening under-lights soccer match last weekend.
I mounted the lens on my monopod for stability and weight.
I chose to capture 'jpg only' for speed, instead of using 'raw+jpg'.
I chose to run it in Tav mode so that I could pick a fairly fast exposure time and a mid-range aperture, letting the camera take care of the ISO.
I did this because I wanted to be able to freeze the action but also get better quality (f8-f11) shots than wide-open.
Well - that was my intention.

No luck.
Most shots were very very dark.
I tried increasing the +/- exposure compensation after reviewing on-camera.
Not much luck with that either.

As the available light diminished, the ISO crept up (I initially limited it to100-1600) and I even tried 3200 later.
Of course the darn shoots became grainier and noisier as dusk set in.
To add insult to injury even after editing in PSE 11 to attempt to adjust exposure, tone, shadows and highlights the PSE11 noise reduction seemed to be completely ineffective.
The odd thing is that when I popped on my very first "newbies long telephoto zoom" - Sigma 70-300 APO the shots were very very much better.

Any advice would be gratefully accepted.


09-04-2014, 07:48 PM   #2
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What metering mode were you using?
09-04-2014, 08:23 PM   #3
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QuoteOriginally posted by mekiAus Quote
Most shots were very very dark.
Is there any chance that you were shooting beyond the available light (Blinking display)? ISO 1600-3200 may not have been adequate if you were shooting f/8-f/11 at any kind of shutter speed in fading light. (I have little feel for how bright the field lighting is in the fabled Vale of Narellan.)

It is also possible that there may be a fault with the lens such that does not stop down properly. Try this:
  • Camera on tripod pointed at a well-lit blank wall
  • Av mode
  • Fixed ISO
  • Matrix or center-weight metering
  • Shield viewfinder opening (thumb or cover included with camera) to avoid biasing the meter with light from the rear
Make a series of exposures (one for each aperture setting) and compare the preview images in group view. The images for each should have equivalent brightness. Alternatively you can take the meter completely out of the picture and do the same test in M-mode adjusting the shutter speed manually to agree with the aperture.

One question...Is the 100-400 lens NEW or used and new to you?

09-05-2014, 08:04 AM   #4
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I think similar as Steve. It sounds like your ISO border was reached and thus the shots were underexposed. With f/8 and a fast shutter speed you need a good bunch of light. Raise your ISO border, because a little more noise is better than a black picture. As mentioned the ISO will start blinking on the display as well as in the viewfinder (at least on my K-30).
You could underexpose by one stop or open the aperture a bit to keep the ISO as low as possible.

09-12-2014, 06:43 AM   #5
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Yes ... You are right Steve and Delegopa. I did another - the nsw first grade women's grand final soccer match on Sunday. My young friend was in the under-17s playing against the Camden Rams, at Leichardt.

I simply ran out of light. Last weekend, in my inexperience, I did not realise the significance of the flashing ISO indicator. At the time I was using the lens, the shooting mode and a heap of camera features for the first time. After your feedback my shots came out exposed correctly. Thank you so much for your advice.

I also learnt why f/2.8 lenses are prized so much ... As dusk fell I was forced to bump up the ISO again and again. Eventually I stopped shooting when 128000 was not enough.

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