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by Jakub

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15,778 reputation
2353
bio website j.mp/NZPHOTOS
location Auckland, New Zealand
age
visits member for 3 years, 11 months
seen 19 hours ago

merge keep
Contact - apptechnz at gmail com <- you know the drill.

Electronic designer. Professional Engineer. Oldish aka "reasonably experienced" :-).
Contact - apptechnz gmail com <- you know the drill.
Tel: +64 9 837 2999 gmt+13

Special interest in technological solutions for developing country applications. Extensive in-China experience in product development & manufacturing in China.

Jack of all trades, Master of Electrical engineering. (aka ME (elec)) Interested in all aspects of modern technology. Professional qualifications in electrical engineering but practically proficient or conversant in many peripheral areas.

Recent extensive experience in solar powered LED lighting development and manufacturing in China for markets worldwide.

"Servant of the Most High God" / committed Christian. Happy to work enthusiastically and interact amicably with people of all nationalities and creeds.

Married with 2 adult children.

Obsessional photographer.


Aug
17
comment What caused dark areas around bright light in this cityscape shot?
Active D-Lighting, or the equivalent feature from other camera makers, should be used with great care if you want to see 'what's really there'. Simplistically - the systems attempts to achieve increased apparent dynamic range overall by adjusting local areas semi-independently. A major consequence can be that areas close to black in one part of an image become less black than other areas of the same actual luminance level in other parts of an image. Scenes that have areas that are close to black to the eye may be lightened and previously unseen unevenness may appear. ...
Aug
16
comment Is it dangerous to do a lens change with power on?
@MattGrum - Sky, dark or light, is seldom present in the wedding reception halls I mentioned :-) (for white balance setting, not cleaning :-) ). I use the sky where it's available for sensor dust image purposes. If the sky has broken cloud then a focused shot will have some detail - but that's not usually too much of an issue.
Aug
16
comment Is it dangerous to do a lens change with power on?
I almost always hot swap. And I do have to clean the sensor more often than some report.
Aug
16
comment Why is the sky in photos always too white?
An ultraviolet filter can help. The UV may not be imaged as visible light but rather be scattered and generally affect contrast.
Aug
16
comment Is it dangerous to do a lens change with power on?
This "wave the unfocused camera for several seconds (is he mad???)" method is also able to give you an emergency white balance reference when a suitable surface is unavailable or you need one urgently. Wave defocused image area over light source of interest for say 2 to 4 seconds. IF the light is "white" a grey card would be properly illuminated. IF the light is not white then you'll get the hue (more or less) that a grey card will see. Useful for eg end of reception dance with disco strobes. This vector sums the lights and gives you SOME hope of being approx right. Some :-).
Aug
16
comment Is it dangerous to do a lens change with power on?
You can do a fair job of simulating an evenly illuminated surface by setting aperture to f/22 or smaller, adjust ISO or whatever until exposure is 2+ seconds, find a moderately uniform target, DEFOCUS onto something else, then point back at target and wave lens to and fro and in 'circles' while the exposure is occurring. The defocused waving gives you a uniform exposure (once you get the feel for the method). |
Aug
16
comment Is it dangerous to do a lens change with power on?
@Chris Better than one photo at f/22, take TWO photos and then swap to and from between them - either a displayed or zoomed in to variable extents. Dust that is in the sensor will be constant between shots. Other source of occlusion (if any) will "flicker" between shots.
Aug
16
comment What is meant by Subjective Image Quality (SQF)?
@dpollitt - Agh - snap! :-)
Aug
16
comment What is meant by Subjective Image Quality (SQF)?
SQF is an attenpt to measure and put a number on the factors that are combined to produce apparent sharpness from a veiwers point of view. It rolls together lens performance (MTF) eye response and resolution and perception and also includes how large the image is and how far you view it from. Look at the references he cites This is a useful introduction and the following page
Aug
15
comment Are fully automatic DSLR lens changers available? What are suitable alternatives?
@BartArondson - Thanks. Yes - that's the basic concept. I don't think most people who decry the "fully automatic" concept have seen what modern automation systems can do, or how compact and powerful an electric drive system can be. Some say they wouldn't sell. I wonder what price they'd need to be to make them saleable. Half the price of a top end body or the price of a good pro lens would get people thinking, I suspect. 1 to 2 second lens changes? Oh yes :-) !
Aug
15
comment Why can't I save video file from canon dslr to computer hard drive?
@Mike - alas even FAT32 has a 4GB limit and all it takes is a somewhat careless programmer and you have a 2GB limit.
Aug
15
answered How is the water effect achieved in “Dali Atomicus”?
Aug
15
comment Why can't I save video file from canon dslr to computer hard drive?
@OH6KVU - yes, thanks - brain fade / typo.
Aug
15
revised Why can't I save video file from canon dslr to computer hard drive?
added 223 characters in body
Aug
15
answered Why can't I save video file from canon dslr to computer hard drive?
Aug
14
comment Why is my SD card filling up too fast?
Most likely "hidden" files as others note BUT there are many fake and clone cards available and you may have one of those - with these anything (bad) can happen.
Aug
13
revised nikon 70-300 f4.5-5.6 vr problem
added 242 characters in body
Aug
13
comment What can be used to “fight” light pollution in astrophotography?
Getting rid of the light is the main fix. A slingshot may work in isolated cases :-). In areas of moderate light pollution where a significant proportion of the effect is caused by light incident on the camera or area immediate to the camera, local shields MAY help. This could start at a matte black painted box or similar around the camera. For the serious, light shielding of a site may be possible (tress or whatever) or good siting. BUT once the light is "in the air" at altitude so that you get a uniform downward "glow", going somewhere better is about the only cure.
Aug
13
answered nikon 70-300 f4.5-5.6 vr problem
Aug
13
comment For the same number of shots, does continuous shooting wear out a shutter or other mechanical parts faster than single shots?
@StanRogers - I'd agree with Stan - but also suggest that the opposite effect MIGHT occur. It would be possible to design a mechanism that it cycled smoothly and transferred energy (say with a buffer block or spring or rotary mass etc) into the mechanical moving parts for the new cycle. Also, some shutter modes in some cameras do not operate a mechanical shutter between exposures in highest speed mode. (The now venerable Minolta 7Hi (not an SLR) has a mechanical shutter whivh was used in all but highest speed burst mode). And some systems (very unnerving) maintain mirror up on fastest burst.