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All things Photography by Thomas Tempelmann


Disclaimer: I am no photographer. I'm a geek who gets excited about the technical aspects of photography.

I own several DSLRs (Sony a55V, Pentax K20D, K-5, K-3), along with an ever growing set of lenses, mainly from Pentax and Sigma. I also own the Gigapan EPIC Pro for taking highly detailed panomamic shots (though I hardly ever get to do that).

1.  Software, Tools

1.1  Applescripts

(probably outdated by now:) A few AppleScripts (for Mac OS X) that assist in identifying missing and duplicate (RAW+) images: AppleScripts

2.  Tips, Hints, Findings

2.1  Various issues with Pentax K-3

I like to document a few issues I have with my K-3.

AF has lost an option over the K-5 (LV vs. viewfinder)

On the K-5 I was able to set up Auto Focusing in a way that's not possible in the K-3 any more, and I really miss that. Here is why:
When I shoot using the view finder, I am used to focus by half-pressing and holding the shutter button, then change the frame and finally take the picture. On the other hand, when using Live View, I usually pre-focus once with the extra AF button and then take several shots, i.e. I do not want the camera to re-focus every time I press the shutter button to take a shot. With the K-5, this configuration was possible: It offered different behaviors for the half-shutter-press for view finder and Live View modes. With the K-3, this isn't possible any more: Either half-pressing the shutter button focuses or it doesn't. Now I always dread using LV because then I have to go into the menu to turn off the focus mode for the shutter and remember to turn it on again afterwards. I wish I could let Ricoh know that this is a step backwards and ask them for a firmware update bringing the old option back.

Shake reduction setting should (optionally) influence Av and P mode's shutter speed choice but doesn't.

In Av and P modes, a shutter speed is chosen by the camera. If the speed reaches a certain threshold value (which is influenced by both the "Program Line" and the "AUTO ISO Parameters" curve settings), the shutter speed held above that threshold as long as the ISO value can be increased instead (when in Auto ISO mode). This is a smart Pentax feature, preferring a noisier picture over a blurry picture (from an unsteady hand) when light conditions get bad. This threshold is influenced by the lens focal length. There is the rule-of-thumb, that the inverse of the (35mm equivalent's) focal length keeps the image sharp: A 200mm lens, when handheld, should use a 1/200s or shorter exposure time. Now, when Shake Reduction is active, this can compensate for two LVs, i.e. a 1/50 would still do with a 200mm lens. The problem with the K-3 is that this SR factor is not taken into account in the above described process: With SR off, at 100mm, it stays at 1/125 while upping the ISO from 100 to 6400. And even if I turn SR on, it doesn't change that - it should then choose 1/60 or even 1/30 so that the ISO can stay low longer. At least optionally.

In TAv mode, when using a flash, the ISO is not adjusted to a lower value accordingly.

In a badly lit room, without a flash, TAv (1/180, f/4) is likely to use a high ISO, let's say 6400, provided the Auto-ISO range allows it. Hovever, if the flash is used, the scene might be well lit even at ISO 100. One would expect that the TAv mode would be smart and would adjust the ISO to the lowest possible setting when the flash is used. However, even with the flash firing, the ISO is left at the setting it would use without the flash. That's disappointing. It also ignores the "AUTO ISO Parameters" curve setting, although that setting could be well applied here.

In TAv mode, when using a flash, the actually used ISO is not shown any more.

Now, with the fact that the ISO setting is not automatically adjusted when the flash is used, the display nontheless does not show the chosen ISO value, but instead just shows "Auto". Contrary to that, the K-5 does show the ISO value even if the flash is active, as ISO 6400. So, the K-3 does hide some important information here - if I'd see that it's choosing ISO 6400 even though I it's using the flash, I would quickly realize that I'm using bad settings and do something about it. The K-5 did. Why doesn't the K-3 any more?

HSS (high-speed sync) flash mode not working in Tv mode under some conditions.

HSS mode is not working in Tv and P (when using the dial to change the shutter speed) modes when the setting C6 (Auto EV Compensation) is enabled and a specific ISO value is chosen (i.e. not Auto ISO).
Turns out that this also happens on my K-5, so this behavior appears to be built into the camera on purpose. While I'm still not convinced of its usefulness (and, especially, it happens quite unexpected, not just for me), there are others who believe it makes sense.
See this Pentax Forum thread for a complete discussion of the behavior.

2.2  Fitting filters on large Sigma lenses

I own the Sigma 150-500mm OS lens, which has a 86mm filter thread. What's little known, apparently, is that there are different kinds of threads used for 86mm: Sigma uses a 1mm pitch, which Sigma also calls 86C ("coarse"), while on eBay you may find a lot of filters and adapters that use a 0.75mm pitch, making them not fit on the Sigma lenses. Furthermore, filters get rather expensive at this large and rare diameter.

Now, this lens is made for full format (FF) cameras, and I use it on a APS-C format camera. Which means that the front diameter is layed out for a wider opening than what's necessary in my case. So I figured that I might try a so-called Step-Down ring to reduce the filter thread to 77mm, for which I own fitting equipment already. I got myself a cheap 86mm-to-77mm step-down ring. Even with a 77mm filter screwed into it, I cannot tell any vignetting at 150mm nor at 500mm focal lengths. Making this a bargain over having to purchase new filters for the 86mm diameter.

The only issue is the aforementioned thread pitch issue: The step-down ring won't fit into the Sigma's filter thread. And I could not find any step-down filter that uses the 1mm pitch. What I found, however, is a 86C (1mm pitch) to 86mm (0,75mm pitch) adapter on eBay. With that, everything fits now, and I saved quite some money on not having to buy a new set of filters.

2.3  AF Fine Adjustment

After spending lots of time adjusting my K-5's and K-3's focusing, I've found that the "Dot Tune" method works best. See here this Youtube video.

2.4  Speedy transfer from memory card to iPad

Apple (and 3rd parties) offer adapters for the iPad for importing taken pictures into the iPad, both for viewing and for temporary storage.

If you're using such an adapter, here's a tip:

If you like to shoot in RAW mode, you may find that importing your pictures into the iPad takes quite a long time. To speed this up significantly, take your pictures in RAW+ (i.e. RAW plus JPG) mode. While this increases the overall memory usage a little, it makes importing into the iPad much faster. That's because the iPad needs a JPG image for viewing. When you give it only the RAW images, it has to generate the JPGs itself, and the iPad's rather weak CPU is taking a long time for that process. But if you give the iPad a set of RAW and JPG images, it'll use the JPG, not needing to reprocess the RAW image. The iPad will import both images, so you won't lose your RAW images this way.

2.5  Using Gigapan EPIC Pro with a Pentax camera in Autofocus mode

I know, taking panoramic shots usually is done with a preset focus, not with auto focus. But when you have a good reason to rely on the camera's autofocus, you might find this not to work with the Gigapan EPIC system, despite their documentation suggesting that it should work. Instead, using the supplied shutter cable, the camera will shoot without focusing first.

The reason for this misbehavior is related to the design of the shutter cable and how cable remotes on the Pentax cameras work: The Pentax has two independent circuits that can be controlled via the remote cable: One for activating the autofocus, and one to activate the shutter. The problem with the shutter cable from Gigapan is that it only serves the latter of the two circuits.

There's a simple work-around, though: Get a mono audio extension cable with a 2.5mm jack. If you use that to extend the shutter cable, you'll effectively shorten the two circuits, causing the camera to apply the autofocus before releasing the shutter. Just don't be surprised that you'll take a picture if you plug this cable into the camera if it's turned on - you'll effectively press the shutter button while pushing the jack inside the plug. Or just remember to turn off the camera before you insert the jack. There's no other harm to expect from doing this, as the cables do not carry their own electrical power but only close open circuits, for which the camera is well prepared.

3.  Pentax (Ricoh) FluCard

I have done some reverse engineering on the FluCard, revealing some additional commands it offers.

4.  Reviews

The Beike gimbal head, along with models by Calumet and Walimex

5.  My pictures

5.1  Gigapan pictures

5.2  Various

Page last modified on 2015-05-17, 10:08 EDT
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