Friday, November 07, 2008

Cheap and Dirty Flashes

I got eleven flash circuit boards from The Electronics Goldmine. They were on sale for $0.79 (79 cents, or PHP 38) each. I bought ten and got eleven.

Each one has a 160uF or 120uF photoflash capacitor, rated at 330V, a tiny inverter, and flash circuitry. It only needs a single 1.5V AA battery to operate. The process is simple: put the battery in, with positive facing the circuit board, depress the metal "diving board" switch on the PCB itself to charge up the capacitor, then short the two dangling wires to fire the flash.

Trivial! I think it's about Guide Number 6 to 8. Quite minimal, but people have made super cheap DIY ring flashes out of these babies.

For my purposes, I'll put five flashes into each ring flash (made from the bottom of a KFC plastic meal bucket). This will also give me two semi-powerful flashes for my ghetto studio.

First order of business was to remove the battery clips, permanently short the flash power switch, and wire the flashes together. I also have to parallel the trigger wires so that the five flashes can be fired simultaneously. So far I've only done the first two steps:

If I'm lucky, I'll get some results this weekend!

Sunday, October 26, 2008

Советский объектив порно

That's "Soviet lens porn" in the title, according to Google Language Tools.

Helios-44-2, 58mm f/2 Zeiss Biotar clone. This one was manufactured by Valdai, Val­dai Op­ti­cal-​Me­chan­i­cal Fac­to­ry, located in Val­dai (may be cur­rent­ly known as Val­dayskaya), about 250 miles NW of Moscow.

Jupiter-37A, 135mm f/3.5 Zeiss Sonnar clone, single-coated. Manufactured by KOMZ, Kazan Op­ti­cal-​Me­chan­i­cal Fac­to­ry. Kazan is lo­cat­ed about 435 miles due East of Moscow, in what was, or is, the Au­tonomous Re­pub­lic of Tatars.

Jupiter-9, 85mm f/2 Zeiss Sonnar clone. This model manufactured by LZOS (Лыткаринский завод Оптического Стекла), Lytkari­no Op­ti­cal Glass Fac­to­ry, based in Lytkari­no, 100 kilo­me­ters north of Moscow.

Mir-1V, 37mm f/2.8 Zeiss Flektogon clone. This is the later, less valuable black MC version. Manufactured by Volog­da Op­ti­cal-​Me­chan­i­cal Fac­to­ry. Lo­cat­ed in Volog­da, ap­prox­i­mate­ly 250 miles NE of Moscow.

All photos taken with a piece of tissue paper as flash diffuser for the built-in pop-up Pentax K10D flash, manual exposure, Carl Zeiss Jena 50mm f/1.8 Pancolar at around f/11.

Incidentally, "Jupiter" comes from the Greek Zeus, which sounded kinda like Zeiss. Creative, comrades!

Although, "Helios" is the Greek name for the Roman Apollo, god of the sun. The Zeiss Sonnar was such-named because it was very bright and fast for its day (which was the early 1930's). However the Helios-44-2 is not a Sonnar, the Jupiter-3 is.

Friday, September 19, 2008

Сравнивая 50mm Гелиос-44-2 на другие обычные линзы

I recently got my hands on a nasty bargain: a 135mm f/3.5 Jupiter-37AM and a 58mm f/2 Helios-44-2 lens for the grand total of $9.00 (actually $17.12 including US shipping, and another 518 pesos for US-Philippines forwarding via Johnny Air Cargo "your friendly e-bay enabler!")

I must say the Helios-44-2 sets a new low in lows in the build quality department. Light years worse than the 1960's Pentax Takumars, significantly worse than my early 1980's East German Zeiss, measurably worse than my early 1990's Russian Jupiter-9 and Mir-1v. Seems after glasnost and perestroika the build quality of Russian lenses actually went up.

It's made of some grotty aluminum alloy (the filter ring was dented, when I tried to straighten it with some pliers, little aluminum bits fell off). The preset aperture mechanism wobbles perilously, the black paint is coming off, and it projects this air of mechanical cheapness. Kind of like a jeepney..

It does have that cool "Made in USSR" label though.

Anyway I just did some sample comparison images, these are by no means definitive.

Rollei 50mm f/1.8 Planar, Singapore, wide-open:

Pentax Super-Takumar 50mm f/1.4, stopped down to f/2 (and yellow cast bleached out with UV light):

Pentax SMC-A 50mm f/2:

Helios 44-2 58mm f/2:

In the sharpness department, the Super-Takumar beats them all, as it's already stopped down one stop while all the other lenses are wide open. It also doesn't have the "bright outline" bokeh that all the other lenses have, it does however betray its non-cool six-blade diaphragm in the OOF highlights.

In terms of overall image quality, I kind of like the Rollei (can't explain it), there's something about that Zeiss quality.. but it's ugly, I took the lens unit of the Planar and stuck it into the (plastic) focusing helical of a Fujinon 55mm f/2.2 which I destroyed, as Rollei SL35 lenses have too short a registration distance for K mount.

But the grotty Helios does show some of that creamy Zeiss bokeh (it is after all a clone of the Zeiss Biotar). Maybe I will always use it stopped down a bit (it has a super round diaphragm like the Jupiter-9 and Jupiter-37AM).

Here's the Frankenstein Rollei at f/2.8 with the Helios-44-2 (that 16-45mm f/4 ED AL makes a nice pedestal for the ancient lenses!)

Still very nice, circular OOF highlights, creamy bokeh.. I think I'm gonna like the Helios-44-2, it's like a shorter Jupiter-9.

Wednesday, August 27, 2008

Pentax 135mm Lens Comparison

Got one of these for a pretty good price. It's not the famous M42-mount Pentax Super-Takumar 135mm f/2.5, but rather the downscale, made in Taiwan, Takumar (Bayonet) 135mm f/2.5. This lens is pretty downscale as Takumars go, being from the budget line. It has four elements in four groups, and was made from 1980 to 1988. Not a classic by any means.

As if I don't have enough 135mm lenses already: I have an excellent Pentax SMC-M 135mm f/3.5, a Carl Zeiss Jena 135mm f/3.5, a Pentax Auto-Takumar 135mm f/3.5, and a creepy plastic $2.00 Hanimex 135mm f/2.8 which is extremely bad. But the Takumar (Bayonet) is a K-mount, not an unhandy M42 mount, and is a stop faster than the SMC-M, so more light and shallower DOF.

But how does it stack up? here are the contenders:

I took some photos of our housing development's water tower, comparing it to the SMC-M. The color cast is different, as the Takumar (Bayonet) lenses did not have Pentax Super-Multi-Coating, but rather an ordinary multi-coating (they are not single-coated, a common rumor, but probably single-coated on the inner surfaces).

Anyway, the full frame:

And comparisons:

f/2.5f/3.5 or f/4f/8

The Takumar (Bayonet) shows some obvious CA wide-open but shapes up admirably at f/4. I cannot really say that the SMC-M (which has a great reputation) wide-open is really that much better than the Bayonet at f/4 (one stop down). At f/8 of course they're pretty much identical.

A good buy, if I may say so myself. That f/2.5 could prove handy sometimes.

Thursday, August 07, 2008

Sub-pixel Anti-Aliasing on Linux

After my accident with the Linux Oracle Binary Image last week, I've been using Linux exclusively on my notebook. It has been somewhat of a pain, but I'm surviving! (quite a feat, after two years of a Windows desktop). I even got the wireless working.

But something has always been bugging me about Linux: how to optimize the Cairo font-rendering engine to get really good anti-aliased text.

Now this may be old hat to the hardened Linux crowd, but it's a sufficiently major discovery for me.

First of all: what is the sub-pixel order? it turns out that the vast majority of LCD displays have RGB pixel order, which is why this is the default.

You can determine the sub-pixel order for your particular LCD by going to this: Lagom LCD test. Windows users don't have to do this, as they have the ClearType Tuning Wizard (not installed by default on XP, but you can get it from MSDN somewhere).

A second important note: (and I just learned this five minutes ago) do not enable full hinting! for some reason, full hinting make sub-pixel anti-aliased text look worse than regular full-pixel anti-aliased text. Although do note that on a CRT, full-pixel AA is the only game in town.

The Lagom site recommends to use "slight" or "medium" hinting. After I switched from full hinting to medium hinting, there was a huge improvement in visual clarity, it's so not funny.

Have fun with your LCD!

Sunday, August 03, 2008

Adjusting Infinity Focus on the Pentax Super-Takumar 35mm f/3.5

I have a Pentax Super-Takumar 35mm f/3.5 lens in M42 mount which I got some months ago. It has been sitting in my drawer all this time because on the 1.5X DSLR it's equivalent to a 52.5mm, which would be interesting except it's slow at f/3.5.

I suddenly got interested in it because of this thread on the MFLenses forum. One of the posters opined that this lens (along with the Mir-1b 37mm f/2.8 which I also have and which also just sits in a drawer) are some of the top wide-angle lenses.

Update: the Mir-1b, which won the Grand Prize at the 1958 Expo in Brussels, is actually a Russian clone of the Zeiss Flektogon.

So I decided to take some photos (out the window) with the Pentax, and quickly discovered that it doesn't focus to infinity. Here's a photo I took with the Super-Tak, the Mir-1b, and the SMC-Pentax DA 16-45mm f/4 ED AL:

The Mir-1b at f/2.8 was sharper, and so was the SMC-DA at f/4. Also it was obvious (from the split-image focusing screen as well as from focus confirm on the K10D) that the Super-Takumar was not properly focused at infinity. Apparently this is a common woe of wide-angle old Pentax lenses.

I found this blog post which details how to adjust infinity focus on a similar lens. The fellow used a sink drain plug to get the front ring off, but I didn't have such a drain plug, so I used a pair of pliers with rubber grips:

Everything else was exactly the same as in the original blog post. Took only about 20 minutes of fiddling to get the right adjustment.

Before and after (100% crop):

Much better!!

That said, I got to try the neglected Mir-1b and it's unexpectedly good! It's extremely flare-prone so I screwed a Pentax hood to the front, making it look quite impressive (almost like a small Canon 17-40mm f/4 L):

It also has pretty good ergonomics, and seemingly better bokeh than the Super-Takumar.

Mir-1b 37/2.8Super-Takumar 35/3.5

Sunday, July 20, 2008

ALP Get-Together at PAGASA

Lalai and I went to the Astronomical League of the Philippines get-together and photo opportunity today, Sunday afternoon, at the PAGASA observatory in UP Diliman.

It's been a while since we were back there, several years at least. The first time Lalai and I went there in 2003, we carried our ETX-60AT telescope in a backpack and took the bus. Something I wouldn't care to try these days..

Several of the members brought their telescopes to use as props for the photo opportunity.

One of the members brought his rebuilt 8" Discovery dobsonian telescope. He built the tube out of plywood and it has a very fine finish. Very much like the telescopes built by Normand Fullum (except without the fauns and fantastic carvings).

I'm very inspired to rebuild my 10" dobsonian (yet again) in this type of format. True, it doesn't break down well anymore, but at least it's solid and holds collimation well. It would take up the entire back seat of our car though, which is quite a negative.

PAGASA has been very much in the news recently because of the sinking of the Princess of the Stars ferry a month ago. The reprobate shipping company has been blaming PAGASA for not forecasting the weather correctly.

The PAGASA observatory seems to have a leaky roof, which explains the plastic water containers distributed over the floor of their building lobby. It's no surprise that PAGASA has shortcomings in the weather department, if they can't fix a leaky roof!

Tuesday, June 17, 2008

Correcting Auto-Focus Errors on the Pentax K10D 1.30 Firmware

I got the suitably-impressive sounding Pentax smc P-DA 16-45mm F4 wide-angle zoom from Francis from the DPP forum for half the local price (and I got free shipping, his cousin Louie carried it here from the US).

It's not as sharp, as weather-proof, or as luxurious as the Canon 17-40mm F4 L that I wrote about in March 2007 but at less than one-third the local price, I am hardly complaining!

The Pentax has the benefit of being slightly wider (25-70 mm equivalent). It has a "quick focus clutch mechanism" which is like a poor man's Ultrasonic Motor, focuses quite close, is decently sharp at F4.. I couldn't be more pleased.

What was less than pleasing was my discovery that it mis-focused a bit. I took a series of photos with autofocus and manual focus (checking with my Chinese split-image focusing screen) and I discovered that the manual focus shots were always, consistently, sharper:

Taken with auto-focus:

and with manual focus:

The amount of mis-focus seems disconcertingly large, but the above shots are at 100%. The actual area shown above are inside the yellow box in this photo:

So the amount of mis-focus is really not a killer; all digital SLR's have some degree of mis-focus; in fact Canon has an "AF shift compensation" menu in their flagship DSLR's (the ones which cost $5,000 to $8,000) so that you can dial in focus corrections for up to twenty lenses. Canon doesn't provide this feature in their lower-end DSLR's (anything that is not an EOS 1-something) because the lower-end models do not officially support split-image focusing screens, so lower-end users can't see in the viewfinder if their cameras are mis-focusing.

Pentax also has such a feature in their $1,000 K20D but only for up to five lenses if I'm not mistaken. The K10D, which is what I have, used to have this focus correction available in the debug menu, but in firmware version 1.11 Pentax disabled the debug menu.

Current firmware is 1.30 so there's no option at all for debug menu. What some people have done is downgrade to a hacked 1.10 firmware, apply the focus shift, then upgrade back to 1.30 afterward to get the Supersonic Drive Motor feature and ISO on the OK button. But it's a hassle.

Thanks however to the famous (or infamous) Pentax blogger RiceHigh, I learned about a Russian utility that enables debug mode on the 1.30 K10D firmware without any firmware downgrades: you simply connect your camera to your computer (which must have the Pentax Laboratory software and the Russian utility) via USB, run the utility software, and et voila, debug mode is enabled.

The trouble is, the debug mode utility was written by some Russians; and my copy of Windows doesn't have Cyrillic font support; and even if it did, I cannot read Russian. This is how the utility screen looks like:

I basically guessed which buttons to push to enable and disable the debug mode; I've numbered the screen so I can explain.

Firstly, you must connect the K10D to the computer (with Pentax drivers) with the supplied USB cable.

Second, always press button 1. Once this button is pressed, the radio buttons (UI elements 2, 3, and 5) become enabled.

Next, select radio button 5, to enable debug mode. To disable debug mode, select radio button 2.

Press button 3 to save your settings.

Press button 4 to exit.

It is necessary to power-cycle the K10D in order to get rid of debug mode (once you've disabled it via the utility).

When debug mode is enabled, disconnect the camera so that you can access the debug menu (press Menu, then select the Setup tab, then scroll to the bottom). The appropriate setting is the AF SHIFT setting.

I did some trial-and-error, and eventually settled on +120um focus correction; this gets the 16-45 AF to agree with the split screen (more or less) and gives relatively sharp photos.

And the final result:

Which is not bad at all! a little more correction (I also tried +160um and +240um) actually works better, but causes mis-focusing at other focusing distances, so the figure I chose was the best compromise I could work out in twenty minutes.

Saturday, May 10, 2008

Back-Focus Issues on Chinese Focusing Screens

I ordered a Virtual Village focusing screen for my Canon EOS 350D, but it arrived after the Canon had been disabled; after I got a Pentax K10D, I used its stock focusing screen plus AF focus confirm for some time, but started to miss the split-image screen, so I ordered another Virtual Village screen, this time for Pentax.

Virtual Village makes relatively inexpensive split-image screens, compared to say the Haoda,, or Katz Eye screens. Inexpensive meaning around one-third to one-fourth the price.

However, the cheap Chinese screens are known for looking "dirty" and having focus issues.

Yesterday I tried using my K10D plus Pentax SMC-M 135mm f3.5 prime, compared to my office colleague's Canon EOS 400D plus 70-200mm f4.0 L IS zoom. Of course my prime cost $40 and the Canon zoom cost $1,000 plus, but I did not expect a huge disparity in the performance, after all a prime is a prime.

But there was a huge disparity: a photo taken with the Canon was visibly sharper even in small sizes. Since I've noticed that my split-image screen does not indicate in-focus condition at infinity with my 200mm prime, I figured that it might need some shims to correct for the back-focus condition.

I found some stickers, cut them thinly, and attached them to the upper edges of the screen (facing the pentaprism):

It does look messy, but the bits of sticker are actually not visible in the viewfinder.

I did some focus testing afterwards. Here's a focus test before adding the shim:

and after:

Could be just me, but the "in-focus" text does look a bit sharper with the shim in place, and the out-of-focus areas in front and behind the text are more symmetrical with the shim: without the shim, most of the in-focus areas are behind the "in-focus" text.

I also noted that the screen now correctly indicates in-focus condition at infinity with a 135mm and 200mm lens.

And now, to test the relative performance of my $12.95 Sears 70-210mm f4.0 zoom, against the highly-regarded Pentax SMC-M 135mm f3.5 prime. Here's the whole photo:

And 100% crops of the top-most microwave dish. With the zoom (wide-open):

with the prime (wide-open):

with the prime (at f/8):

The SMC-M prime doesn't give up a lot, wide-open, and it's a lot sharper than the zoom, which is to be expected.