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05-10-2012, 01:07 PM   #1
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Fast Lenses

Hi

as I'm thinking about finding some odd/non mainstream glass for me to play around with, or going on a bokeh hunt, just wondering what the fastest aperture on a lens is that won't cost a bomb?

Also, can anyone please suggest any interesting lenses that I could research? I'm getting a little bored of my 55mm prime

Thanks

05-10-2012, 01:11 PM   #2
Ash
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Get an old Super Takumar 55 f/1.8 (unless you already have it) or the various Pentax 50 f/1.4 or 1.7 lenses going for cheap - the marketplace here is full of them. Very cost effective option.
05-10-2012, 01:22 PM   #3
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Bokeh hunt you say? While it may be not the fastest lens in the world for its focal length, the Helios 44 certainly has a very special out of focus rendering.

05-10-2012, 01:56 PM   #4
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This lens probably has the best value-to-quality ratio:
SMC Pentax-M 50mm F1.7 Reviews - M Prime Lenses - Pentax Lens Reviews & Lens Database


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05-10-2012, 01:56 PM   #5
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I agree, the Helios 44 is cheap fun, I should use mine more.
05-10-2012, 02:01 PM   #6
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Bokeh is the rendering of OOF (out-of-focus) areas of an image. The thinner the DOF, the more of the image is OOF, so faster lenses usually give more (if not necessarily better) bokeh. 'Good' bokeh is defined as, "If I like it, it's good!" Many demand smooth, creamy bokeh. I like contra-bokeh: smooth bokeh if the subject is complex, nervous bokeh if the subject is smooth and bland.

We sometimes think of old lenses with zillions of iris blades as BOKEH MONSTERS!! Especially those without auto-apertures. The iris blades in such lenses are usually positioned further forward than in auto-aperture lenses. Many of my Bokeh Monsters are in Exakta mount, though some are M42 or M39 or even T-mount. Blade-count isn't the total story; that's just a rough generalization. And lenses with edge-to-edge flatfield sharpness (macro and enlarger lenses) usually have rougher bokeh than lenses with more field curvature.

So, tools for more (and maybe better) bokeh include: faster and/or longer lenses for thinner DOF, and older lenses for whatever effect iris blades and their placement have; and forget about enlarger lenses.

I can throw in a trick here: front-loading (screw-on) optics to thin the DOF. A +1dpt closeup optic pulls-in the focus distance to about 50-95cm, making even the DA18-55 an interesting close-protrait lens with bookoo bokeh. A good 1.5x screw-on TC (like my Sony VC-1546A) stretches the focal length, turning my K50/1.2 into a 75/1.2 monster. And my 15-blade Meyer Trioplan 100/2.8 becomes a razor-thin 150/2.8 with a magickal glow. Ooh la la!
05-10-2012, 02:31 PM   #7
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I have the Pentax-M 50mm f1.7 that Adam mentioned, its a lovely lens! Here are some shots I took with it:
500px / Photo "Accidental light expulsion" by Stolpulus II (this one is droplets on a window, with street lamps in the background)
500px / Photo "Big one day" by Stolpulus II (and this one has the subject isolated by using DoF)
All processed in post, of course.
There are some f1.4 and f1.2 lenses, but those skyrocked in price and rarity. But honestly, even a 50mm f2 will give plenty of bokeh. I just find that old lenses tend to give more pleasant bokeh than a lot of the modern digital ones. Also, tele lenses tend to produce more blurring, so maybe look for legacy 85mm or 135mm. But generally the lenses with the largest apertures tend to be in the 50mm range and cost a lot.
05-10-2012, 02:44 PM   #8
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I have 2 Helios 44s... (the -2 and the -5) they are different from each other and both quite fun. I don't think any suffers as much from astigmatism as your, kcobain1992, though.

Another soviet lens that I like for portraits is the Jupiter 37A, a 135 3.5 -- also very unexpensive, and that DOF is thin enough for me. No coating on mine; find that the (very common) flare can sometimes even be creatively exploited.

QuoteOriginally posted by RioRico Quote
A good 1.5x screw-on TC (like my Sony VC-1546A) stretches the focal length, turning my K50/1.2 into a 75/1.2 monster. And my 15-blade Meyer Trioplan 100/2.8 becomes a razor-thin 150/2.8 with a magickal glow. Ooh la la!
I have never used a teleconverter, but don't those things reduce your effective aperture? So that the K50 1.2 would turn into a 75 1.7?

05-10-2012, 03:22 PM   #9
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QuoteOriginally posted by RioRico Quote
Bokeh is the rendering of OOF (out-of-focus) areas of an image. The thinner the DOF, the more of the image is OOF, so faster lenses usually give more (if not necessarily better) bokeh. 'Good' bokeh is defined as, "If I like it, it's good!" Many demand smooth, creamy bokeh. I like contra-bokeh: smooth bokeh if the subject is complex, nervous bokeh if the subject is smooth and bland.

We sometimes think of old lenses with zillions of iris blades as BOKEH MONSTERS!! Especially those without auto-apertures. The iris blades in such lenses are usually positioned further forward than in auto-aperture lenses. Many of my Bokeh Monsters are in Exakta mount, though some are M42 or M39 or even T-mount. Blade-count isn't the total story; that's just a rough generalization. And lenses with edge-to-edge flatfield sharpness (macro and enlarger lenses) usually have rougher bokeh than lenses with more field curvature.

So, tools for more (and maybe better) bokeh include: faster and/or longer lenses for thinner DOF, and older lenses for whatever effect iris blades and their placement have; and forget about enlarger lenses.

I can throw in a trick here: front-loading (screw-on) optics to thin the DOF. A +1dpt closeup optic pulls-in the focus distance to about 50-95cm, making even the DA18-55 an interesting close-protrait lens with bookoo bokeh. A good 1.5x screw-on TC (like my Sony VC-1546A) stretches the focal length, turning my K50/1.2 into a 75/1.2 monster. And my 15-blade Meyer Trioplan 100/2.8 becomes a razor-thin 150/2.8 with a magickal glow. Ooh la la!
Awesome post.. thanks RR
05-10-2012, 03:40 PM   #10
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QuoteOriginally posted by c-meier Quote
I have never used a teleconverter, but don't those things reduce your effective aperture? So that the K50 1.2 would turn into a 75 1.7?
Rear-mounted TCs eat light. Front-mounted optics don't. Front-mounted wide adapters cause lousy edge effects. Front-mounted tele adapters don't. IQ loss is minimal -- I just punch-up contrast and saturation slightly, if needed. That's with name-brand thread-on tele adapters: Sony, Canon, Olympus, Kowa, Schneider, etc. Beware, cheap no-name glass still sucks, usually.
05-10-2012, 06:29 PM   #11
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Budget Bokeh?

Hi Gil, this is a question that's right up my line. I'm a sucker for unusual bokeh and who doesn't love a bargain?
There's a $50.00 (give or take) lens that will provide you with a very unusual lens effect, bokeh included; The Sears 135mm f/2.8 auto MC Macro, aka "The Glow".
With most back-lit or side-lit photos, this lens (in Macro mode, a slight additional twist of the lens front) will generate a soft, surreal halo or golden aura around the lighted areas. It's hard to describe, but a Google search will turn up plenty of examples. The glow is most prominent on the in-focus subjects, softer and less distinct on the out-of-focus areas.
The Sears lens also comes in a non"A" version and I understand it's the same optical formula, just as much glow. Then there's a non-macro version, no glow.
A conventional (non-macro) lens that's a fine all-around short telephoto and has beautiful bokeh is the Pentax M 100mm f/2.8. At f/2.8 up to f/4.0 it has wonderful soft OOF highlights and a very sharp and clean in-focus rendering. Great SMC colors, too, but be sure to use a hood. About $100.00 for a good one.
Have fun!
Ron

Last edited by rbefly; 05-10-2012 at 06:36 PM.
05-10-2012, 08:00 PM   #12
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QuoteOriginally posted by rbefly Quote
There's a $50.00 (give or take) lens that will provide you with a very unusual lens effect, bokeh included; The Sears 135mm f/2.8 auto MC Macro, aka "The Glow".
Oh darn, that's the one I sold because it didn't pass my PF test! And the buyer was so happy to get it! If only I'd known. What a fool I was! That's what I get for ever selling PK-A-mount lenses. I'll never do THAT again!

I've heard (but haven't yet tried the mod) that slightly changing lens element separation distances can induce such a 'glow'. I've thought to sacrifice an extra M50/2 for experimentation -- for the sake of Science, of course.
05-11-2012, 08:49 AM   #13
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The Samyang 85/1.4 has exquisite bokeh. Manual focus only, but rather inexpensive.
05-11-2012, 08:58 AM   #14
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we really need Gil to come back with his definition of cheap and fast.

I have several 28mm lenses that were cheap < $15 and fast at F2.5 and one at F2, but the natural DOF of a 28mm leaves the out of focus region a long way back.

In more "normal lenses" a 50mm F1.4 is relitively in expensive at 50-100 depending on make etc.

As Rio said, you can look for bargins in old preset lenses with round apertures, I find many of these have more pleasing out of focus rendering, perhaps a little softer than newer lenses. Look at the 135mm Lens club, I compared a Tele Lentar 135/2.8 preset against an SMC Tak 135/3.5. At any given common aperture, the out of focus rendering of the Tele lentar seemed softer, even though the image itself was equal in sharpness.

preset 135's can be had for about $50 or less. Other focal lengths are not as common and more expensive.
05-11-2012, 09:32 AM - 1 Like   #15
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I agree with rbefly, the Sears A 135mm macro is worth a look. Sharp, good colours (but lacking contrast compared to modern lenses), smooth bokeh and the bonus "glow effect". It's very easy at this focal length to blur the background.

Sears macro glow effect:



More photos here: https://picasaweb.google.com/bonhommed/SingleInSeptember2011#

For something completely different, try the Kiron 28mm f2. It's sharp from wide open, colours are cooler than Pentax, bokeh can get wild at f/2, but I like the effect.

Kiron 28mm @ f/2:



The Kiron's bokeh is more conventional when stopped down. More samples here: audiobomber's Album: Single in November - PentaxForums.com

Both of these lenses NEED a hood to miinimize flare. I still need a telephoto length hood for the 135mm, but a standard 50mm hood, 55 mm filter diameter, works great on the 28mm.
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