pathology_doc: Ginny Weasley (film) clutching Riddle's diary: Ginny/Horcrux OTP (Default)
I've done a little field experimentation with this thing in rough-and-tumble land, and have made the following discoveries.

1) The grip of the retaining magnet to the adhesive mounting ring is not quite what it could be. They really need a pair of magnets, so the two will lock together centre-to-centre at once and stay that way - the distortion when off centre is remarkable, and it shows a tendency to shift if you repeatedly pick the phone up and put it down. OTOH it seems to slip only minimally under gravity, if at all. In this sense, something optimised to mounting on a single model of camera (like the Olloclip is for the iPhone) is far superior.

2) I took pictures of things at various distances. Depth of field is short at anything less than arm's length; reliable, blur-free hyperfocal distance is at least the length of a tall man's arm. This lens is probably a better match for phonecams that have some sort of autofocus capability than for fixed-focus types.

3) Lens flare LIEK WHOA.

4) The lens cap stays on fine (good), but is occasionally a little slow to peel off if you have very short fingernails that tend to break.

In short, it is still a compact, cheap and convenient way to slightly extend the range of your phonecam if you're not contemplating trading up in the mobile phone world. But you should be aware of its limitations, and also those of your cellphone's camera - because the two tend to add at least, and occasionally to multiply.
pathology_doc: Ginny Weasley (film) clutching Riddle's diary: Ginny/Horcrux OTP (Default)
(Discovered fortuitously this afternoon.)

When carrying two or more sets of rechargeable AA or similar, it may be an advantage to ensure that they are of different brands or in some way differentially marked. I have two sets of Energizers - one bought here in Canada, the others holdovers from Australia. I accidentally spilled them into a pile and had to work out which were the flat and which the charged. Fortunately the latter had just come off the charger and were palpably warm (and now both sets are good to go), but when scrabbling around in your camera bag without a table to dump things on, it's vital to know, if they get mixed up, which set you just took out and which you want to put in.
pathology_doc: Ginny Weasley (film) clutching Riddle's diary: Ginny/Horcrux OTP (Default)
Today was the first day in quite a while that I could take a walk around more than a short block without the certainty that the skies would open and drench me. (I almost took the chance yesterday and was lucky I didn't.)

I took my *ist-DL and just about all my lenses with me (where is my 55mm f1.7 standard Pentax lens?). Thank God for Tilley's Vest of Many Pockets (or VOMP). Aside from one short interval where I switched to the Sigma kit lens that came with the camera, I mostly used my 70-210 manual-focus lens. It goes without saying that because this thing was designed for a film camera, the effective focal length is more like a 105-315mm zoom.

Now I've played around with it a bit on a stationary target, so to speak, but how would it go on an extended field test shooting multiple different things at various focal lengths? More importantly, how would I go after years away from manual focus lenses?

The result was not actually bad, and some of what happened was enlightening. Even with the ISO dialled right down to 200 (as low as the camera will go), the first few shots were clearly overexposed when I zoomed in on the preview screen. So I dialled the exposure compensation down a stop and a half, which took me down to ISO 80 or so. That seemed about right, as far as I could tell, so I left it at that.

"As far as I could tell" brought me onto an other interesting problem, about which camera reviewers on YouTube complain, which is the difficulty of seeing the preview screen in bright ambient light. This really is a problem, and for some compact digitals it allegedly seriously impairs the ability of the user to frame the shot properly or judge the adequacy of the one they've just taken (and after today, I believe it).

This left me in a very interesting position; namely, exactly where I used to be when I was shooting my film SLRs back in the day and didn't know what I was going to get until after the shoot was complete and I had gone home. Of course this time I had two advantages - I had almost limitless shots available (over a thousand, on two SD cards) and the time between finishing the picture-taking and being able to review the results was very much foreshortened (I stopped at the local Tim Horton's for an iced lemonade and, being indoors, was able to examine the outbound shots free of the glare problem). And although I couldn't examine the shots in detail in the field, I could at least zoom in on the previews and know that I was close to a decent exposure.

On the way home, the sunny day came to something of an end. Things are now very different to how they were this afternoon, when I was shooting Canso waterbombers against a generally blue sky, and now we have this:

I finished with the EV meter almost back at 0.0 again. Before I dialled it down, some of the brighter colours (reds and yellows) were very vibrant, practically fluorescent. When the walk was done, I'd have had to dial overexposure to get that result.

The lens performed well, for the most part. I had the camera set to aperture priority, primarily for depth of field control, and the other reason I had to cripple things down to an effective ISO of 80 was that it was so bright I had problems opening things up for narrow DOF. When I say 'for the most part', what I mean is that most of the best shots were taken at the shorter focal lengths. By the time I was out at 210, they were somewhat fuzzier. I'm not sure whether this was the deliberate compromise of the designers or a general function of how non-proprietary long focus zooms behave, and I didn't have my tripod with me to go for a slow, stopped-down shot.

The performace at the 70mm end, however, is nothing short of outstanding. At 70mm it's close to being my best lens. It's also half a stop faster at the long end than my 18-250 do-everything AF lens (5.6 vs. 6.3), which might or might not be worth the extra 40mm.

If I ever find that Prime lens, I'll take that out for a play. That will definitely not be a lens for a bright day, unless at very fast shutter speeds and small apertures. Or with the EV turned all the way down, which ought to put me around an ISO or ASA of 25.
pathology_doc: Ginny Weasley (film) clutching Riddle's diary: Ginny/Horcrux OTP (Default)
This is one of my two fixed (prime) lenses, the other being my macro, and because of the relatively wide aperture it is my low-light lens if I anticipate not being able to use flash much. It's also a very small and flat lens to have on the camera (the smallest in my personal experience, although Pentax have since gone one better), which makes for ease of handling. I keep a sacrificial 49mm UV filter screwed onto the front at all times, to catch anything which might be thrown up by the wheels of passing cars or careless small children smearing grubby fingers everywhere, and have since replaced the unusual screw-on lens-cap with a more easily replaced standard-type after-market spring cap.

Okay, let's see what it can do. I set to aperture priority at ISO 200, and shot with the aperture all the way open and all the way closed. I centred the reticle in the viewfinder on the large building at the top of the hill for both shots, but I suspect the spot focus was reading the sky somewhere and it shows.

Cut for photos/length; all worksafe. )

...and thus as a side benefit, we have a lesson in why you use tight f-stops for landscape photography. You might be able to see that despite my focus point being in the distance, the wheels of the cars in the car park are now much more in focus. Go back and look at the first shot, and you'll see what I mean. (It goes without saying that if I were doing this as a formal project, I'd use a tripod and cable release.) Conversely, if I want to isolate a subject, I'll be sure to crank the thing wide open for minimum depth of field (one of the benefits of this lens) and get close.

In this particular case, I might have done well to overexpose by a stop or so, given the general greyness of the weather.

If I were buying this lens again, I might go for the slimline pancake-flat version. The only reason I didn't was that I didn't then know it existed (and it may not have existed when I bought this one; I'm not exactly sure).
pathology_doc: Ginny Weasley (film) clutching Riddle's diary: Ginny/Horcrux OTP (Default)
I have quite a few leisure interests, and one of them is photography. Because I have small children whose growth I want to record and because I do quite a lot of photography in my day to day work (especially when I have a lot of coronial autopsies), the camera has recently been getting quite a workout.

Back in the days of film, I started out with the usual addiction to Kodacolor Gold 100. It was cheap, available, and you usually got a "free" roll built into the cost of your photo processing. That was until I pushed my mother's little instamatic way, way beyond the level of what it was really meant to handle and got quite a few underexposed shots.

And so I discovered high ASA. 200, then 400 (which I stayed with), and rare forays into 1600 whenever I could get my hands on some. As time went by, I got myself a good SLR camera (a Minolta Dynax 3xi), and then (oddly enough) I went back to a semi-manual Pentax (P30T, I think), with which I had a hell of a lot of fun. And because I had a way wide open (f1.7) lens for it, my hunger for higher and higher ASA film ratings went away quite a bit.

Cut forward quite a few years and (after many twists and turns) I became the proud owner of a Pentax *ist-DL digital SLR. Cool beast, only 6MP, but it accepts the older lenses (and even gives me in-focus indications, though I have to do the actual focusing myself) and does everything I need it to do. The only thing, of course, is that it has a 3200 ASA equivalent setting for the sensor, and so the old disease took over - mostly because the lens it came with was no faster than f4 or thereabouts, and because a later lens (a do-everything 18-250mm) is a horrid f6.3 at full zoom and those high shutter-speeds are really important to prevent blurring.

Just the other day, I pointed it (fitted with a 40mm f2.8) out the window and took several shots at the various ASA settings, then expanded them to see what the "grain" was like. First, here is the 200 ASA shot (taken through flyscreen, unfortunately, which is why you will almost certainly see a "gridded" effect in the sky).

Cut for long post and plenty of pics. )

I suppose if you want that grainy early 70's look on blowing up your prints, this is the way to go. But if you were trying to focus on one detail in a larger field or to use expansion as a substitute for a zoom lens you weren't carrying, you would soon run into terrible trouble. The Pentax K-5 is said, after updates, to be able to handle a blistering 51,000 ASA. Sounds fascinating, but even with eight years of advances in digital image sensor and in-camera processing technology, I shudder to think of what the grain on that would be like. On the other hand, it would also be able to do things on the slower side - and having a 100 or even 50 ASA setting would provide some really crisp shots on those days that I have enough light to use it.

On the Gripping Hand, I almost never print anything bigger than a 6 x 4 glossy (sometimes I go up to 5 x 7), and the biggest laptop I or anyone in my family has is about a 15" screen. So even at 200 ASA, my resolution and grain are probably never going to be enough of a problem to go up to that juicy K-5 and its 16 megapixel sensor...


pathology_doc: Ginny Weasley (film) clutching Riddle's diary: Ginny/Horcrux OTP (Default)

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