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Forum: Pentax SLR Lens Discussion
02-25-2008, 10:26 AM
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That might explain my experience. Periodically it fails to flash even though the light is still on. I assumed that one of the connectors has pulled lose, turn it off, check the connections, turn it on and its fine. Maybe the TR3 has the same quirk. Maybe its a power-saving feature.
I absolutely love the Illumisphere. It works exactly as advertised although it robs you of a lot of lumens. Money well spent. I plan to order the internal reflector for it. I think that will be handy when using it for fill in sunlight.
I checked out your webpage. Prince Edward Island! In would love to go there sometime, maybe in my boat. Beautiful place!
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Forum: Pentax SLR Lens Discussion
02-25-2008, 06:02 AM
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The flash set-up was really a nice surprise. :D For most shots I used the Illumisphere straight-up vertical without its end-cap. For the long shots down the aisle I also shot with the 'sphere pointing outward, those usually turned out best.
Tripack? Right, I couldn't think of its name. The TR3 seems highly-priced at $150 but it does the job and its probably a low-volume item for Pentax. At the time I bought it, none of the third party flash battery makers new anything about the 540FGZ and could not guarantee compatibility. I've probably shot over 300 pics with it. I am still on the first set of 6 c-cells and just started seeing the recycle times fall-off. I was tempted to buy rechargable batteries, but it doesn't seem necessary. If I start doing a lot of flash work then I'll step up to a higher capacity rechargable product.
Bonus: (Well, I guess that depends on your point of view) The Gary Fong Illumisphere attracts a lot of attention and proves to be a good ice breaker.:cool:
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Forum: Pentax SLR Lens Discussion
02-25-2008, 04:09 AM
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I shot an indoor boat show this weekend exclusively with the Pentax 10-17. I took the 18-55 and assumed that was going to be my primary lens but no. Mostly I wanted to shoot everything at 10 because I was trying to either capture the 'size' of the show or because I was shooting something close (everything is close inside a show). Mostly I only zoomed-in to eliminate some vertical from the edge of the photo. My flash set-up worked great (540FGZ with a Gary Fong Clear Lightsphere on the tripack battery.)
Here's the slideshow. About 10-15% have been 'defished' to some degree in PS and anything with a vertical near the edge has been cropped.
smile-123- powered by SmugMug |
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Forum: Digital Processing, Software, and Printing
02-19-2008, 08:58 AM
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IMATCH at photools.com - Solutions for Image Management and Digital Photography. is a very comprehenive photo database that provides extensive meta data editing capabilities and macro development tools. I happen to be a smugmug user and I noticed recently that an API interface for IMATCH has been developed. It does have a learning curve that may not be worth the effort if all you want is a library listing of thumbs.
The tool has a pretty big following, i.e. discussion groups, and I've always received good support from them. Finally, it is in its Nth revision and I consider it a mature well tested product.
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Forum: Post Your Photos!
02-18-2008, 03:53 PM
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Actually, this is a case of my idea being better than the end result, if you know what I mean. I was looking for either a suggestion that might get me pointed towards some progress or a consensus to throw it away.
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Forum: Post Your Photos!
02-18-2008, 09:25 AM
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A provocative title always helps, huh? My new 10-17 zoom started me thinking a little surreal so I played with PS for an hour and this is the end result. Monday Morning Violet filter on the woods, screen the water for intensity, color burned sky for intensity. K10D, Pentax 10-17 (at 10), tripod, f4.5, 1/350th, tripod. Original first.
Keep it, change it, or just throw it away?
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Forum: Pentax DSLR Discussion
02-10-2008, 04:10 PM
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The only literature I've seen about the Pentax Image Stabilization feature is (1) that it gains you 2-3 fstops of useability and (2) that in some instances you may want to disable it. Its this last part that I wondering about. You would think that above some shutter speed, the anti-vib would be disabled. Is it? You would also think that the system would decrease the vib sensitivity as shutter speed is increased.
Some of my pics show definite vibration at, what I would think is, sufficiently fast enough shutter that it shouldn't be there, say 1/3000 at 500mm? Yet I see this doubling or tripling effect that sure looks like camera shake.
Does anyone know more about how this works, specifically if it automatically cuts out?
I have always left the anti-vib ON except in a few long-exposure tripod mounted situations. I am thinking that perhaps I should normally leave it off unless I am in a specific situation that needs it. Anyone have a 'best-practice' opinion?
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Forum: Photographic Technique
02-10-2008, 03:52 PM
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I haven't read anything from Pentax about how they are using the CMOS sensor, but I have a technical background in them from way, way back in the early days when they were making these devices literally one at a time. I did see that the k20D will have a 14 bit A/D instead of the 21 bit A/D in the K10D and that let's be jump to some conclusions.
From the A/D side of the CCD, ' dynamic range' is simply the range of light intensity that can be registered by the device from a single bit on to all bits on, and that's a pretty wide range when you consider they are using a 21bit A/D. I can't convert that to lumens or anything, but its a big range. Here's where the problem comes in. In order to reduce that to reasonable ranges, in the case modeled after ISO film speeds, the processing engine selects a sub-range of that data and essentially discards all the other information above and below that range. You are afterall, going from a numerical range of 2**21-1 to 2**8-1 (the ** here represents an exponent, i.e. 2 to the 21 power). But, the CCD actually sees the entire range of light all the time. The CCD sensitivity is very noisy under low light (small numbers) plus A/D conversion adds noise, then there's noise introduce by limiting the range of A/D output, and again by conversion in the processing engine.
The case of A CMOS sensor is a little more complex because the senitivity of the device can be adjusted with its bias voltage. Need more sensitivity? Just increase the bias voltage which also helps to keep the device from operating in its noisy range. You no longer have to accept the entire physical range of the device in order to extract the data that is appropriate for any desired ISO speed which allows use of lower resolution A/D converters which give less noisy, more linear results, and all this requires less post processing (i.e. noise reduction in the engine).'
In theory, the CMOS should be a far superior sensor that produces far less noise.
WARNING: I am an old fart and its been a long, long time since I studied this stuff.
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