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10-16-2011, 04:38 AM   #16
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QuoteOriginally posted by axl Quote
Well, for 100mm and over the f2.8 is actually considered fast, and for 300 definitely!

Anyway, easiest way on fueling...ehm, fixing...this lust is to start with fast-ish primes, such as F/FA50/1.7, F/FA28/2.8, maybe DA70...and then you'll lust after 55/1.4 or 50/1.2, maybe 77ltd or 85/1.4...

It never ends, now that you are hooked on, all you can do is to get some ocasional "fix" through some purchase...good luck
As Peter says, you can often find deals on older lenses that are plenty sharp. The DA limiteds, while not as fast are sharp from wide open as well and quite a bit cheaper than the FA limiteds.

Still, I'm afraid that LBA has begun and you are hosed!

10-16-2011, 09:42 PM   #17
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QuoteOriginally posted by Jonathan Mac Quote
1. Sharpness is not everything in a lens.
Yes, but you can eliminate more lenses from consideration based on sharpness than by any other criteria.
10-16-2011, 10:30 PM   #18
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QuoteOriginally posted by axl Quote
Well, for 100mm and over the f2.8 is actually considered fast, and for 300 definitely!
This raises a question: What is the theoretical focal.length vs max.aperture vs frame.size basis for calling a lens 'fast'?

I know my 28/2 and 85/2 and 135/2.5 are fast, but faster glass exists around those FLs. Even my 50/1.2 can be beaten, and it's what I would call ultrafast. And a 50/0.95 would be hyperfast or something? My 120/1.8 is fast; are my 200/3.5's fast, or just middling? And if I whip out some cheap smaller-format lenses, are they really fast? Like a 15-25/1.2 and 25/1.4 and the 6.5-13-26mm f/1.9's? Has anyone come up with criteria for judging fastness?

QuoteQuote:
Anyway, easiest way on fueling...ehm, fixing...this lust is to start with fast-ish primes, such as F/FA50/1.7, F/FA28/2.8, maybe DA70...and then you'll lust after 55/1.4 or 50/1.2, maybe 77ltd or 85/1.4...
As mentioned, it's even easier (or at least more affordable) to lust after fast manual lenses. My Kiron 24/2 wasn't really cheap at US$125. The Komine 28/2 CFWA ($18) and Nikkor-O 35/2 ($48) and and planar Yashica ML 50/1.4 ($10) and Tomioka 55/1.4 ($2.25) and Nikkor 85/2 ($9) and S-M-C-Tak 135/2.5 ($50) were certainly reasonable. Anyway, AF is for elitist snobs lacking MF skills. [/me hides a dozen AF zooms]

QuoteQuote:
It never ends, now that you are hooked on, all you can do is to get some ocasional "fix" through some purchase...good luck
LBA is not a disorder in need of a cure. It's a demon that needs to be fed! And I enjoy every morsel. Well, most of them, anyway. [/me wonders what to do with those CCTV lenses]
10-16-2011, 11:38 PM   #19
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Anyone any idea how much the Reyxar 50/0.75 Or XR Heligon 100/1.5 (or similar lenses) are worth? And more readable info? Thanks.

10-16-2011, 11:53 PM   #21
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QuoteOriginally posted by hoanpham Quote
Anyone any idea how much the Reyxar 50/0.75 Or XR Heligon 100/1.5 (or similar lenses) are worth? And more readable info? Thanks.
They're probably worth more than I am.

I bought a Rodenstock XR-Heligon 120/1.8 a few months ago for US$38 shipped. Yes, it's VERY fast and large, weighing almost 900g after I removed as much excess hardware as possible. I glued a PK macro tube to it to direct-mount it on my K20D with a fixed-focus of about 50cm / 20in. (I put rubber bands around the lens body to stabilize it within the tubes.) An interesting lens, yes...

At about the same time, I bid on a shorter faster XR-Heligon, around 75/1.2 I think it was, but IIRC that sold for over US$400. I'm not sure if the shorter lenses are any easier to use, if they can be focused out a bit further. I could move the focus out if I cut away maybe 2mm from the rear-element housing. Yes, I should do that.
10-17-2011, 12:21 AM   #22
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How far can they focus from their original hardware housing?
I guess that they are made for xray machines, and manual focus distance would be limited, or if they do have manual focus at all. I dont mind using my feet to focus ;-)
Does Rodenstock make lenses with aperture blades (XR Heligon)?
10-17-2011, 12:54 AM   #23
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LBA starts here. lol
I used to use 55-300, then i switch to 80-200/2.8

I used to think M50/f2 is very good. Then I got M50/1.7, A50/1.7, TKM50/1.4, FA50/1.4, and now my K50/1.2.... lol


Last edited by MegaPower; 10-17-2011 at 12:59 AM.
10-17-2011, 01:08 AM   #24
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Doom us all.
After i got the K28/2, i stop looking for pentax glasses. Still missing AF lenses, Ltd, and longer/better than A*300/4.
I am pretty done with the Pentacon set. 7 lenses incl carl zeiss 300/4, all accs, 2 bodies.
Got a lot of Zuikos, incl 55/1.2 and 35 shift.
Got some funny comments while shooting pentax with nikkor 50/1.4.
About to get some unique nikkor 100-105 DC, 105/1.8
Now looking for trash xray machines.
10-17-2011, 03:07 AM   #25
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QuoteOriginally posted by hoanpham Quote
How far can they focus from their original hardware housing?
I guess that they are made for xray machines, and manual focus distance would be limited, or if they do have manual focus at all. I dont mind using my feet to focus ;-)
My XR-Heligon 120/1.8 might focus to infinity on an EOS maybe, and certainly on an m3/4 or NEX, which could support focusing helicoids. Or just cheat and use nested PVC pipes as the focusing body.

QuoteQuote:
Does Rodenstock make lenses with aperture blades (XR Heligon)?
Funny stuff results when we search Google or eBay for XRAY LENS -- mostly, many offers of IR filters for seeing through clothing. Right. Some of these are VERY VERY EXPENSIVE, like US$400 or more for a 720nm IR-pass filter that otherwise sells for US$30. Nice profit!!

Speaking of money, when I search eBay for XRAY LENS I find a Meopta Stigmar 75/1.1 and a Rodenstock XR Heligon 75/1.1 each at US$35 with 6 days left, and a Carl Zeiss Jena 100/0.73 lens that may be Xray or copy, for US$150. That last is rather heavy at 8.2kg. Other real Xray-machine lenses are listed also, at much higher prices.

I don't think XR lenses have iris apertures. I'm still researching that. But when gargling for XRAY LENS HELIGON IRIS I found this interesting thread on mounting and using such lenses.

QuoteQuote:
The XR-Heligon and TV-Heligon lenses are special purpose lenses for a past generation of X-Ray machines... These lenses are VERY fast, are optimized for excellent image quality at infinity, and have a very short back-focus. By back-focus, I mean in this case the distance from the back of the lens to the image plane when the lens is focused at infinity. I read one quote of 7mm back-focus at infinity.

So, when mounted on Nikon with 46.5mm from the mount to the image plane, this lens is fixed focus at a very close distance, is subject to flare, shows curvature of field, and little sharpness away from the center. Why would anyone want it? It produces a dreamy smooth bokeh.
There is much good information at the above links. Have fun!
10-17-2011, 03:35 AM   #26
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Ohhh....now you did it.......
10-17-2011, 08:01 AM   #27
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@OP: LBA is an addiction !! It is a unquenchable desire to add to your lens collection. Am sure many, many here are afflicted by it !! Just ask RioRico :-)
10-17-2011, 10:18 AM   #28
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LBA is not an affliction to be cured, but a glorious demon to be happily fed! The feedstock can be cheap or costly, doesn't matter as long as it's chewy.
10-17-2011, 10:57 AM   #29
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QuoteOriginally posted by Jonathan Mac Quote
Sharpness is not everything in a lens. This tends to be forgotten nowadays because itīs easily measurable, while many other qualities are not.

Perhaps said qualities are not measurable because they are imaginary.
10-17-2011, 11:08 AM   #30
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QuoteOriginally posted by stormtech Quote
Now I've done it......

Through my short journey with Pentax gear, I started with the basics with a DA 16-45 and DA 55-300. I've throughly enjoyed these lenses.

One of my goals this past summer was to shoot my wife's many flowers - bought a DFA 100 2.8 for that and love it. But...I started judging all my photos with the other lenses against the sharpness of the DFA 100. Since using that lens for a few months now, I've been very critical of all my photos for sharpness - is this some kind of disease?

Now it gets much worse. A couple days ago I received a Tamron SP300 2.8. This lens gives my the type of sharpness that makes the hair on the back of my neck stand up - ohhhh how I love it.

So now, I wonder if there is any going back. I've killed my budget for lenses (actually a bit overkill), but now all I can think about is how to replace that 16-45 and 55-300 with killer sharp lenses.

Heck, I almost sold one of my cars this week so I could go after some more killer glass.

Am I screwed now?
Yep. You're screwed. The key is however to only buy what you Know you will use. Don't go about it my way and buy just in case type lenses. I have a lot of nice glass but it does sit an awful lot.

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