Lightnings taking a ride

by ceinmart

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15,878 reputation
2453
bio website j.mp/NZPHOTOS
location Auckland, New Zealand
age
visits member for 4 years
seen 22 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
22
comment What are hidden-gem “bang for the buck” lenses for Nikon?
If I get specific I'll miss the secret gems you know about. What's really cheap and really good :-) ? I noted that an entry level 50mm will probably happen soonish. eXAMPLE: in the Minolta lineup there are old mid range well priced zooms that excel. The "beercan is a 25+ year old 70-210mm f/4 . Here's a comparison test with a more modern Canon 70-210mm From about $150 on ebay. 4.55/5 user ratings on 339 REVIEWS!
Aug
21
asked What are hidden-gem “bang for the buck” lenses for Nikon?
Aug
21
awarded  Convention
Aug
21
revised Picking a new primary zoom lens for D7000
added 1039 characters in body
Aug
21
answered Picking a new primary zoom lens for D7000
Aug
20
answered Should I buy a adapter ring with or without AF confirm?
Aug
19
comment Is it worth keeping the original packaging for gear such as lenses and camera bodies?
Boxes can often be carefully flattened by undoing selected seams, and then rebuilt using eg EVA adhesive. This is usually only useful if space is at a premium. I have done this when buying equipment while travelling and not having had room for it in assembled form.
Aug
17
comment How to identify a fake LP-E8 Canon battery
@jrista - Yes. I agree. I've seen the shoddy fakes with NimH - perfect looking Sony battery copies - but weight was the give away. Wityh LiIon camera abatteries I have had many "clones" that say eg "FOR Sony". These have had similar capacities when new but pooer calendar lives - ie after a few years are more liable to be low capacity. These are hard to spot when new - and usually give good value for money. About 3x to 6x less cost when new.
Aug
17
answered How to identify a fake LP-E8 Canon battery
Aug
17
awarded  Enlightened
Aug
17
comment What caused dark areas around bright light in this cityscape shot?
... A related effect is that areas of close to constant luminance may have subtle details removed. eg When taking pictures of Polynesians with relatively uniform brown skin tonings I've found that Sony's "D-Range Optimizer" when set to its most aggressive level tends to make faces or arms look like slabs of coffee coloured skin. Worse with flash. The same setting works well in increasing apparent dynamic range on image areas with a reasonable level of variation and no large areas with little variation.
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