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  1. #76
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    Thanks Bob.

    It's a Pentax K100D Super. Set at the max of 6 MP.

    Will post a crop later. Will also do some shots in RAW and with ambient light just for interest.

    Yesterday I used a Lumix with the same light setup; same problem.
    Cheers, Ern

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  3. #77
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    Ern, I think you will find that shooting RAW files will be the partial answer to the colour cast issues. When adjusting the 'tone' setting you should be able to remove the cast.
    All the best
    Kevin

  4. #78
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    Kevin, the camera offers 'bright' and 'normal' and I've been using normal. Is that what you meant? Or in post-processing?

    ..

    I took some shots in RAW. The best colour cast came with light from a shaded side window through the side of the tent and auto white balance but the shot was still very contrasty despite this being set to lowest. I think a bit of chatoyance in the timber is contributing to this. I can reduce it a bit on the PC and playing with hues helps but it still ends up an unrealistic representation.

    Crop attached Bob.
    Cheers, Ern

  5. #79
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    Hi Ern, It would be in post.
    Here is a screen shot of the Photoshop settings that come up when I open a RAW file. Move the temperature to get close to the colour balance you like and fine tune with the tint settings. This is just a basic starting point. Longer exposures, >5 secs, introduce some interesting colour casts.
    As for getting it right at the source its tuff to get it 100% correct unless you use a colour meter reading and calibrate the camera white balance to that reading(I'm not sure your pentax allows for this?). It will take in the ambiant light, the colour bias of your light source and the colour cast created by the reflected light off the light tent. Get as close as you can at the source and fix it in post. Every lens adds its on own colour cast, every screen does the same and every print media adds to the mix.

  6. #80
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    Thanks Kev.

    I used the RAW manipulation s/w that came with the camera which is a bit limited. PS needs a mod to handle Pentax RAW so I'll try and do that.
    Cheers, Ern

  7. #81
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    I've just started using PS on RAW files with my new camera, and think that a lot of people's problems with color could arise due to not having their screens calibrated correctly.

    What you see on the screen is not necessarily the correct colors as recorded by the sensor, and needs to be calibrated against a known standard color chart. Only then will the visual adjustments you make in PS be correct.

    To calibrate a screen, you display the known color chart (electronic), then hold a sensor over the different colors. The software will tell you what adjustments are needed to get correct calibration. I have 2 monitors on my computer, and there is a vast difference between the rendition of the same photo on the 2 screens.

    Now saving up to buy a calibrator (wouldn't mind sharing the cost & equipment with another user cos you don't need to do the calibration very often.

  8. #82
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    Allan, I have a Spyder2express you're welcome to borrow.

    Review: http://www.northlight-images.co.uk/r...r2express.html

    You also need a decent monitor it should go without saying.
    Last edited by rsser; 3rd February 2011 at 02:54 PM. Reason: additions
    Cheers, Ern

  9. #83
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    That's great, thanks for the offer Ern. Current LCD monitors are fairly old and nothing special. I'm looking at upgrading later in the year so might take up your generous offer then (though this might bring the upgrade forward a bit).

  10. #84
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    Default Another tip...turn vibration control off if camera is on a tripod.

    Got caught out for my last few pictures.....couldn't work out why they weren't perfect....I was using tripod, remote shutter release, narrow aperture for depth of field, etc, to photograph some before and after shots of fuming oak with ammonia.

    Then I worked out it was because the vibration control on the lens was on....vibration control should be switched off when the camera is not hand held.

    I did some comparison shots...there is a very marked improvement when vibration control is off.

  11. #85
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    Quote Originally Posted by Peter Jennings View Post
    Got caught out for my last few pictures.....couldn't work out why they weren't perfect....I was using tripod, remote shutter release, narrow aperture for depth of field, etc, to photograph some before and after shots of fuming oak with ammonia.

    Then I worked out it was because the vibration control on the lens was on....vibration control should be switched off when the camera is not hand held.

    I did some comparison shots...there is a very marked improvement when vibration control is off.
    Interesting point you raise Peter, I've heard that point raised before. I'd be interested to see some side by side comparison shots if you have any. You can post them in this thread, or, better still create a new thread in the photography forum.
    I leave the OS (Optical Stabilisation) on on my 17-70 Sigma all the time whether it's being hand held or on a tripod and I've not noticed any problems. Although I will say that apparently some lenses are smart enough to know if they're mounted on a tripod they automatically disable I/S-O/S, don't know if my lens is one of them .


    "Many modern image stabilization lenses (notably Canon's more recent IS lenses) are able to auto-detect that they are tripod-mounted (as a result of extremely low vibration readings) and disable IS automatically to prevent this and any consequent image quality reduction.[11] The system also draws power from the battery, so deactivating it when it is not needed will extend the time before a recharge is required."

    From this article

    https://www.woodworkforums.com/f122/i...6/#post1595243
    Last edited by Grumpy John; 8th January 2013 at 05:08 PM. Reason: Added link to Photography Forum
    To grow old is inevitable.... To grow up is optional

    Confidence, the feeling you have before you fully understand the situation.

    What could possibly go wrong.

  12. #86
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    Thanks John. The lens I used was a Tamron Di 2 18/270 zoom. It does say in the lens instructions to switch off Vibration control (equivalent of Canon's Image stabilization) when tripod mounted, to stop those busy little gyros spinning. I use very slow shutter speeds, up to 4 seconds, to get maximum depth of field with a narrow aperture, and this may have made the blurring effect of the vibration control worse.

  13. #87
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    No probs Peter. I'm not an expert by any means, just putting in my two bob's worth.

    FYI
    Last edited by Grumpy John; 9th January 2013 at 07:01 AM. Reason: Added youtube link
    To grow old is inevitable.... To grow up is optional

    Confidence, the feeling you have before you fully understand the situation.

    What could possibly go wrong.

  14. #88
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    The mirror flipping up may be enough to blur a 4 sec exposure, even on a tripod.
    Solution is to manually lock the mirror up before exposing. I've been doing twilight exposures up to 30 sec; any where I forget to lock up the mirror are slightly blurred.
    I usually switch off image stabilisation, focus (auto), switch off auto focus (care not to adjust focus setting), lock up mirror, then expose (using a remote release).

  15. #89
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    i think the term is parallax. a problem with anything other than an SLR.

  16. #90
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    A couple of other big thing is to not create hot spots and to use a COPY of your photo and play around with your background to see if you can really make it pop.

    Not everyone can afford a professional setup. Not to worry. A PVC framework with covering works well. Using crumpled up 18" wide tinfoil that is then spread out again and pasted to the walls of your booth or onto some foam board you can bounce your lights off of those and you should not see hot spots if done correctly. OR drop some white cotton cloth over a frame and shine your lights through that.

    GIMP is an OpenSource (free download and use) software very similar to a very expensive PhotoShop package. Learning to de even simple tricks in such a package works wonders on your photos. I've seen a photo that was very dark spring out of such using just ONE TOOL in Gimp. ALSO, you can delete backgrounds easily although it takes time usually. Sometimes you can re-do the background with a simple FILL command using a paint bucket. BUT, once you've cleared a background you can then fill with various colors to see what makes your item pop out.

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