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/2.5	f/3.5 or f/4	f/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.

Mike Johnston Is Back!

And here's one of his latest writings: How To Stress A Camera Lens. I've been a huge fan of Mike's work at photo.net and at Luminous Landscape. I used to follow with bated breath his weekly column, The Sunday Morning Photographer.



Of course it helps that his taste in lenses hews closely to mine. The 50mm f/1.4 Super-Takumar is one of his all-time favorite lenses. It's heavenly!

He has a new review of the 35mm f/2.8 SMC-DA Macro, where he enthuses,

If you'd actually like to buy this lovely device, please link from here so we can rake in the profits. I'll go mad I'll be so awash in money. I'll buy a sailboat. O what heaven the sea....

That's not something you see in an everyday camera lens review!

Anyway, the lens they're all gushing about is $540. Cheaper than that 50-135mm f/2.8 DA* SDM I've been lusting after, but not by much. And it's still the price of a Russian 135mm f/2.8 Tair-11A and an East German 75mm f/1.4 Zeiss Biotar put together, with perhaps some room to spare.. or closer to home, the SMC-DA 35mm f/2.8 costs as much as a Leica Elmarit-R 180mm f/2.8 which will almost certainly appreciate in value over the years (and in the meantime will make a killer portrait lens).

Oh well. Mike is still great.

SCTEx

Drove to Subic last Friday for a client presentation. Was the first time I've taken the Subic-Clark-Tarlac Expressway, which is indeed a modern motorway very much like those I've seen in China, HK, and Malaysia.





Of course it was a Friday during work hours, but entire expanses of the expressway were completely deserted (unlike, say, NLEX).



I also got to play with the GPS on my mobile phone, and discovered that at (moderate) speeds, the car's speedometer is within 2 km/h of the GPS reading.



I actually hit 150 km/h on SCTex (for a while, there are supposed to be radar speed traps). The underpowered MZR-Z6 was turning at around 4,500 rpm at that speed. A far cry from the 364 km/h posted maximum speed on SCTex (by a BMW X6, incidentally I saw one at Pacific Star last Thursday).

The Blue Light

I have an excellent Pentax Super-Takumar 50mm f/1.4 normal lens from the late 1960's. I got it on e-bay for a relatively low price.

Just this morning, after reading an extremely informative thread on the Manual Focus Lenses forum, I was finally able to verify that, based on my lens' serial number of 37801, it is one of the earlier Super-Takumars with radioactive thorium glass in one of the high-index elements.

Turns out, the yellowing of these radioactive lenses is actually the reaction of the Canada balsam (a tree sap, used to cement lens elements together) when it gets bombarded by particles over a period of time.

Prolonged exposure to ultraviolet light actually bleaches the Canada balsam (UV light is well-known to fade dyes and other polymers), so the yellow cast disappears.

Here's a comparison of the Super-Takumar with an SMC Pentax-A, which shows the slight color cast of the Super-Tak:

Super-Tak:


SMC Pentax-A:


The Super-Tak has an obviously warmer cast (which lots of people like, incidentally..) but a histogram shows that it's only about half-a-stop faster than the SMC-Pentax (which is an f/2 lens), probably due to the yellow cast absorbing some light. I don't like my f/1.4 lens suddenly becoming an f/1.8 lens, so I decided to try to bleach the yellow cast out of it.

People supposedly expose their lenses to sunlight (which is rich in UV) for weeks or months at a time, but it's rainy (typhoon season) and besides I don't have a window which sees constant daylight. Also the lens would get wet as it rains in the afternoons (and I can't keep the lens behind the window, as window glass blocks UV).

Anyway, I went to Ace Hardware to look for a black light and found this:



It's an "Omni" brand bug zapper bulb, 25 watts and 220 V, quite cheap at 70 pesos (about $1.50). It's not quite a black light, as it's an incandescent (not surprising given its rock-bottom cost!), so it has really pitiful UV output. However, I think it's still better than sunlight:

The mean solar constant is 13.67 lumens/square centimeter. A 50mm f/1.4 lens has a front element that's 36mm in diameter, which gives an area of 1,000 square millimeters or 10 square centimeters. So if the Sun's rays are fully perpendicular to the front element, at most 137 lumens of solar energy goes into the glass, not all of which is UV of course.



My bug zapper bulb is 25 W, since it's an incandescent it's quite inefficient and would only put out about 8 lumens/W or 200 lumens. Only a small fraction of that is UV light. But I can make certain that this light is always going into the front element.

I put aluminum foil (shiny side down) over the front element of the lens, as I'll send the UV light in through the back. The discolored element is supposedly somewhere in the back.



I took a cardboard tube (actually an old piggybank that I got for exchange gift in Mozcom about five years ago) and lined the insides with aluminum foil, shiny side in:





By doing this, I'm hoping that a good fraction of the bug zapper bulb's luminous flux will end up inside the Super-Takumar, rather than being uselessly dissipated into free space.

And the piece de resistance:



It's The Blue Light!!!



(fortunately Hitler won't see this)

Update: 13 September 2008

What I didn't mention after I posted this is that the UV light from the incandescent bug zapper did not provide any more improvements to the color cast. That cheap bulb had just too little UV output to bleach the yellow-colored Canada balsam.

Last week though, while on one of the usual lunchtime Power Plant expeditions with Dennis, I found a fluorescent UV lamp at True Value. The shelf guy said it was used for money detectors and such. It was 6W and T-5 form factor. I figured that it would have about the same light output as a 30W incandescent bulb, but due to the more efficient UV emission of charged gas versus a hot tungsten filament, it would put out a lot more UV.

And I was not far wrong. After three nights of bathing under the relatively cool light of the UV fluorescent light (no electric fan cooling needed) the lens was obviously almost yellow-free.

Super-Tak:


SMC Pentax-A:

Super-Tak after UV treatment:

Actually the above photo is too blue (must be a white balance issue). But if it's blue, it's not yellow! (they're opposite)

Here's a photo taken with the Super-Tak after the UV treatment:

and compare with the output of the SMC Pentax-A 50/2 (a bit dimmer because I used the same shutter speed for both, and the Super Tak is an f/1.4 lens):

As Borat might say, Great Success!

Pacific Star Series

These are a series of photos I've taken from the 19th floor of the Pacific Star Building in Makati.

Hidden enclave.





Hot air.



Republic of Makati.



Seedy hotels.



Gas station.



Laundry.



Taken with the Communist Kombinat Volkseigene Betrieb Carl Zeiss Jena 135mm f/3.5 Sonnar, and the Volog­da Op­ti­cal-​Me­chan­i­cal Fac­to­ry Mir-1b 37mm f/2.8 (a Zeiss Flektogon clone).

A Walk in the Park

Normally, I exit the office past 6:00 in the evening, but Lalai usually doesn't get off work till past 7:00 or 8:00 p.m. Since parking on the street in Makati is free after 5:00 p.m. I normally park the car in Salcedo Village (near the Peak Tower, where the Mozcom offices are) and take a nap.

Unfortunately it gets hot inside the car; I also don't want to leave the engine running because that sort of thing is hard on the engine and besides, gasoline is expensive.

This afternoon, while waiting for Lalai to be finished at work, instead of an uncomfortable nap, I went to Jaime C. Velazquez Park (where Ineng's Barbecue became famous, way before they had a store in Market! Market!)

Since I had my camera with me, I decided to amuse myself in the waning afternoon light.









Moon over Leviste Street (apologies to Sting).

Non-Working SD Reader & FaceBook

I wanted to transfer some photos from my K10D to my notebook. I used to do this using the Tecra M6's onboard 5-in-1 card reader. But now I'm in Linux land, and, surprise, the "Texas Instruments PCIxx12 SDA Standard Compliant SD Host Controller" does not work. The tifm driver from Berlios won't compile either!

I tried using Pierre Ossman's sdhci driver (which did come with the Oracle Binary Image kernel) but it doesn't work.. in fact it hung my notebook good.. so much for Linux hardware advances. Although of course this is mostly TI's fault, as their SD controller chip doesn't have open specs (probably due to the DRM issues with Secure Digital and Memory Stick Magic Gate).

Out of sheer frustration (and boredom) I signed up for FaceBook. They certainly have a very slick interface. It's so much better than that old warhorse Friendster that it's not funny. The only drawback is the fancy FaceBook interface eats CPU; since my notebook has CPU throttling and fan control, when I'm on the FaceBook site the fan is always spinning up and creating noise like a tiny turbine.

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!

More German Antiquities

I happened upon a Schneider-Kreuznach 135mm f/4.5 Xenar on the usual place when the auction was almost ending. Got it for $9.00 (plus the caveats about shipping).



According to this web page on the Schneider site, this lens was made sometime after November 1951, and before May 1952. A real antique!

It has a preset diaphragm, lots and lots of diaphragm blades (like the Russian lenses), and the (uncoated) front element is deeply set and so a hood is probably not needed.

It was in Exakta mount, but I did a temporary work-around by wrapping snippets of business card around the Exakta bayonet and then push-fitting an M42-Pentax K adapter ring over the business cards:



Wobbly, and it doesn't quite reach infinity focus.

From the performance of this lens, it is an uncoated triplet, very much like the Zeiss Triotar. It has low contrast wide-open, and is not as sharp as its East German sibling, the Zeiss Jena 135mm f/3.5 Sonnar.

Zeiss Sonnar	Schneider Xenar

Probably interesting for portraits and I'm eager to see its bokeh. I assume the bokeh is very nice, given the circular diaphragm opening.

I had some high hopes for "retro photography" with this lens, but bad luck reared its ugly head. While I was fiddling with it today, the front element fell out (my fault) and gained a large edge chip (a more accurate way of saying that is, "Orly unscrewed the front retaining ring, turned the lens over to look at something inside, and the front element fell on the floor and a piece of its edge got broken").

Technical me knows that such a chip (I even blackened it for good measure) has no effect on the photos, but that chip just reduced the lens' resale value by a huge amount. Not that I'm complaining, having gotten it for $9.00 - but it really was worth around $80 (I just got lucky on the bid), and I was hoping to build up a collection of antique lenses for future generations.

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 37/2.8	Super-Takumar 35/3.5