Alley in Pisa, Italy

by Lars Kotthoff

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2,410 reputation
1917
bio website
location Norway
age
visits member for 3 years, 2 months
seen Jun 5 at 1:25

Hobbyist photographer back in the '70s and '80s. Took my first photo when I was five years old, got an SLR when I was ten. (Film, all manual, handheld light meter, we had a darkroom in the basement.)
Shelved the hobby for a couple of decades. Returned recently, this time with digital equipment.

Jack of many trades (and master of none), but I have a professional background in software development.


Jul
19
comment Nikkor lenses: is there any means to know if a lense mount is in metal or plastic
I'd ask both you and Rockwell: Why does it matter? Plastic can be lighter, cheaper and adequately strong. I think the "plastic is bad" phenomenon is similar to the "digital is bad" known from digital/film photography or vinyl/CD music: Based more on emotions ("when I was young we used to...") than on any measurable fact. (I remember one guy complaining about early CDs that they didn't have the vinyl scratches before the music started, which he had grown accustomed to as a sort of Pavlovian anticipatory trigger.) If you still want metal, Rockwell's site is the best that I know of.
Jul
17
comment What are the clues to look at regarding how long Canon's EF/EF-S lens mount might be current?
@Aphex5 Too much opinion IMO. "Never ever" is obviously false, "not this year" is obviously true, anything between is a random guess. The Canon FD mount lasted 16 years. The Nikon F-mount has lasted 54 years so far, the Canon EF-mount 26 years. Changing mounts is enormously expensive for the manufacturers, as they have no lenses for their new mount, and spend a decade or so to fill the catalog. They will change eventually, when forced to, but will hold on to their mount as long as possible. For EF-S, I'd be more worried that I might want a full frame camera within the next decade or so.
Jul
13
awarded  Custodian
Jul
13
reviewed Approve suggested edit on How can I make my Coolpix focus after I'm in place for a time-delayed self portrait?
Jul
12
comment How do sharpening tools work?
@jwenting What's the difference? Wikipedia says that edge enhancement works by "increasing the image contrast in the area immediately around the edge". Granted that it's local rather than global contrast. But it's still contrast, isn't it?
Jul
11
answered How do sharpening tools work?
Jul
11
comment Looking for lighting for 3-light setup
It's possible. According to a Lensrentals blog post - lensrentals.com/blog/2013/07/… - they made a 43,000 Ws flash unit during WWII for air reconnaisance, it could illuminate subjects 6 km (4 miles) away. Weight more than a metric ton, though, so not very portable. In practice, I think I would buy a few 1000W worklights and a diesel generator, and send an assistant to position them at the mountaintop, communicating over cell phone or walkie-talkie. Would be semi-portable, at least.
Jul
9
comment What do the markings on a Tamron CCTV lens mean?
@Mzk 1) Formula for f-number is the same, independent of DSLR or CCTV. 2) Some DSLR lenses cannot change aperture directly on the lens, only indirectly from the camera. But 3) it appears that the manual iris and auto iris specifications are for two different lens models - one manual, one auto. So I guess yours is the auto iris model. See their catalog (pdf) - one auto, one manual iris version of each lens.
Jul
9
comment What do the markings on a Tamron CCTV lens mean?
@Mzk You have the lens, why don't you try and see? For DSLRs, some lenses change max aperture (the f-number) as you zoom, other lenses keep it constant. To keep it constant, the lens has to change the effective diameter when zooming. 'F 1.4-Close' certainly means that max apt. is f/1.4. I can't tell from the specification whether that's a constant f/1.4 through the zoom range.
Jul
9
comment What do the markings on a Tamron CCTV lens mean?
@Mzk The f-numbers is what is listed in the specification as 'aperture range'. Yes, the effective diameter needs to change when the focal length changes to retain the same f-number. Either the lens does that automatically, or the f-number changes when you zoom. Not familiar with CCTV, but assume aperture works like for DSLR lenses: An iris like the 'nine-bladed iris' animation here: en.wikipedia.org/wiki/Diaphragm_(optics) that can step through the standard progression of f-numbers from your link - 1.4, 2.0, 2.8 etc.
Jul
9
comment What do the markings on a Tamron CCTV lens mean?
@MizukiKai I guess 'close' means that the iris can be closed completely, so there's no light coming through at all. If so, I assume all the intermediate apertures are available as well.
Jul
8
answered How weather resistant is the Canon EOS 7D?
Jul
6
comment Birding on a budget?
What's wrong with leaving the question as is? It's got three good answers for three different budgets: Bridge camera, Sigma Bigma and 70-200/2.8 with 2x TC. Don't they collectively cover pretty much the entire space of what 'budget' could mean? For future visitors through Google, aren't these good answers to "I'm not a millionaire, but I'd like to shoot birds - what are my options"?
Jul
3
awarded  Fanatic
Jul
3
awarded  Enlightened
Jul
2
awarded  Nice Answer
Jul
1
comment Is there a program that does automatic adjustment of levels in a batch?
Both Google's Picasa and Adobe Lightroom have an 'auto' option. In Lightroom, at least, you can apply it in bulk. For some photos it works very well, for others it's just awful. Automatic good settings for every picture is not feasible, IMO, but it can save editing time for the pictures where it works.
Jul
1
comment What do I need to take photos which accurately show small differences in color?
@JamesSnell I guess it should work if you use consistent lighting. Haven't tried, so I can't really comment beyond that. But you might want one anyway to calibrate the monitor.
Jun
30
answered How to take extreme (multiple month!) long exposure photos?
Jun
30
comment How to take extreme (multiple month!) long exposure photos?
@StanRogers You're right, I was off by a couple of stops; thanks for catching it. Do you happen to know how low-sensitivity it's possible to make these plates, is there a minimum? (Agree on the reciprocity failure. Found a "simple model for t>1 second" here, I assume that's for the same development. Brings the number of stops of ND down to a reasonable range.)