Wednesday, November 02, 2011

Macro Focus on a Cameraphone

In a discussion thread on Google+ about android phone apps,  Remi Valade asked about android cameras apps with a macro feature. Since close ups are a feature I often use/need I figured this was something worthwhile investigating. I am a geologist and I often need to take close up pictures of rocks, not works of art so much as photos  that show the specific detail. I recently found this exotic rock (ie it did not match the local geology) in the spoil of shells and charcoal below an aboriginal midden, in a large dune blow out. It is highly weathered, but looks hard and probably volcanic, when I turned it over I could see what appears to be a skilled chipping of the edge to produce a cutting or scarping shard, maybe even a spear tip. By the way when taking “scientific” close ups, it is good practice to include a scaling reference, such as a coin or pencil, or make up you own scale reference, laminate it and keep it in your camera bag
Close taken with my DSLR A bit closer with HDR Camera on my Android Phone
Searching google and just doing an android macros focus query then looking in various forum, It show that the common complain was that whilst the screen could be focused on something close, it would usually drift out of focus when the button was pressed (and the delay before the shutter fired) and the photo was taken. I wondered if this was a camera movement thing, up close even a small movement would mean a close object could go out of focus and refocussing takes time. I also noted the large number of Phone magnifiers app that seemed to display similar focus sensitivity and short comings. This got me thinking perhaps I might do better moving back and using the zoom.
I had already discovered that if I pressed and held my finger on a specific part of the image the HTC camera would focus and set the exposure  to suit that point (and it could be anywhere on the screen), Then after a short delay (maybe 3 seconds) still hold my fingure on that spot on the screen the shutter would fire, with flash if necessary. The press and hold is a much easy way to stay steady, and I use it all the time. Adding a bit of zoom gave me a quiet acceptable photo of the chip. You can see the texture of the split and several phenocrysts in the unweathered part of the rock.

Very close taken with the HTC camera and a bit of zoom
My next stop was the android market place, and using the key words Macro Focus. I  saw there where only a few camera apps claiming macro capabilities amongst a larger number of magnifiers. The most obvious free photo app (I wanted free so I could test it out) was PRO Paint (they have a paid app version called Pro Zoom Camera 5X). First results where awful, every time I focussed and tapped the screen to take the picture it would go out of focus (just like the user comments in the various forums) plus the frequent nagging screens suggesting I upgrade where driving me crazy. Eventually I pressed the AF button (I now realized it stood for AutoFocus) down on the far left and it worked beautifully (see below). Ok about as well as the HTC camera held steady (see above). Anyway I don’t like nagware so I have delete this app already.
Taken with PRO Paint in AF mode
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