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01-04-2013, 09:55 PM   #1
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SLR Magic 35mm T0.95...will it work for K-o1?

Hello,

I am posing this question to someone with perhaps a better grasp of mounts, focal length conversions and risk of vignetting when using various lenses. I recently became aware of a lens that has not yet been released from a company called SLRMagic. It looks like it is made for a crop sensor, APS-H, sized, and I am unsure, but I believe this is a hair larger than the APS-C sized sensor in the k-o1. In any case, according to the attached link, these come in Leica M mount standard (because they are apparently more easily adapted to any other mount...the "o-negative" of lens mounts...universal donor, I guess -- according to Steve Huff) but will ship with an adapter of your choice. As usual, Huff (who panned the K-o1) doesnt mention the K-o1, instead rambling off a bunch of M43 cameras which cost 4x as much as the K-o1. In any case, I am just curious if anyone knows whether the design of this lens is compatible with the sensor/distance from the mount to the sensor of the K-o1. The price is too good on this lens to pass up, but too steep if it is going to have unacceptable vignetting and/or chromatic aberrations/distortion due to an adaptation mis-match.

In any case, the obvious appeal of a 35mm at f0.95 is pretty much enough to make anyone chomp at the bit a little. All the same, this is a $1400 lens....and $1400 is $1400 (which isnt $10k for a NoctiLux, but all the same....$1400 for a manual lens). In addition to whether this lens will work with the K-o1, I was hoping maybe someone who has experience with various fast lenses can chime in on a few issues I have heard about when it comes to these types of high-end lenses (currently, the fastest lens I have is the Pentax M 50mm f/1.7. Very pleased. Havent taken it out in the dark yet, but so far very pleased with it). In any case, the issues I have heard about are as follows:

--Lenses (including the original Leica NoctiLux 1.0) of this nature tend to be optically corrected to their lowest aperture and are mediocre at best stopped down. The proprietor of a local photo shop here in town who claimed to have owned a full Leica rig with their fastest lenses advised me that Leica even warned their prospective customers about this issue, as opposed to other manufacturers who simply omitted this. My question therefore would be: Is this something that is of concern when selecting a lens below f/1.4..f/1.2 range?

--On the K-o1: With the aperture being open all the time....the risk of leaving fast lenses wide open while shooting. I stop my 1.7 down to f/22 between shots and point it at the ground to avoid overexposure to the sensor. I have heard that sensor burn is a load of horse nuggets and also that, since mirrorless cameras tend to be open all the time for live view, that they are more prone to damaging the sensor due to overexposure. In any case, I started stopping down to avoid accidentally pointing it at the sun wide open while not paying attention when I first noticed that the 40mm f/2.8 seems to exhibit this behavior (the camera seems to stop it down at shut-down and as the light changes even if I have it set in manual mode). This lens I think only goes to f/16...

--Are ultra-fast lenses like this simply over-rated, or are they simply aesthetic choices that one makes when assessing their approach to the medium, much in the same way as a painter selects pigments...(for instance, the pigment cobalt blue not having any inherent superior 'blueness' over cerulean blue, but is simply more expensive as a result of its rarity, archival permanence, refractive and mixing qualities and so on...). The same photo-shop proprietor as above also advised me that for low-light photography (unless doing low light action photos) to buy the slowest lens I can and shoot it at around f 5 and deal with having super long exposures. As I do enjoy low light photography, preferring to venture out at night and tend to photograph dark areas during the day (alley ways between skyscrapers I find tend to have very interesting light, although even in full sun, they tend to be dark enough to require an ISO of 800 with the f 1.7 wide open), I tend to agree with his assessment, however, I was hoping someone might be able to shed some light on his recommendation: In other words, if assessing a fast lens simply on account of its low-light performance, he claims, that lenses in the aperture range of 1.2 to 0.95 are simply not as versatile as slower lenses stopped down. Can anyone make an assessment of this and recommend whether the designation of f/0.95 is really all its cracked up to be, or whether it is so much Pavlovian marketing jive that magically relieves the financially over-endowed of the better parts of their financial *ahem* "burdens" as it were--regardless of whether it really the feat of optical engineering that the manufacturers claim it to be.

In any case, I am hoping someone with more experience than myself can maybe chime in on the topics of whether this lens is compatible with the K-o1, and if so, whether it is a desirably lens on the K-o1?

Thanks!

Greg

The new SLR Magic Hyperprime 35mm T0.95 and 35 T1.4 arrives for testing! | STEVE HUFF PHOTOS

01-04-2013, 10:21 PM - 1 Like   #2
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In order for a lens to be adapted to another camera mount the Flange Focal Length must be greater than that of the camera it is being adapted to. M mount is 27.80mm and K-01 is 45.46mm. So I do not see how this will work without corrective optics which sort of defeats the purpose.

Not sure I understand the universal donor thing either. M mount certainly could be adapted to m4/3, Nex (E-mount) and even the Pentax Q but that hardly makes it a universal donor. M42 is far more adaptable from Flange Focal Length standpoint.

Now sticking this on the Pentax Q would be interesting.
01-05-2013, 12:14 AM - 1 Like   #3
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QuoteOriginally posted by cristigj Quote
--On the K-o1: With the aperture being open all the time....the risk of leaving fast lenses wide open while shooting. I stop my 1.7 down to f/22 between shots and point it at the ground to avoid overexposure to the sensor. I have heard that sensor burn is a load of horse nuggets and also that, since mirrorless cameras tend to be open all the time for live view, that they are more prone to damaging the sensor due to overexposure. In any case, I started stopping down to avoid accidentally pointing it at the sun wide open while not paying attention when I first noticed that the 40mm f/2.8 seems to exhibit this behavior (the camera seems to stop it down at shut-down and as the light changes even if I have it set in manual mode). This lens I think only goes to f/16...
I have an old Praktiflex film SLR that the mirror stays up on after a shot and comes back down when you wind to the next frame. Shutter curtain pinhole burns are a problem on those cameras because if the mirror is up and out of the way, nothing is blocking the shutter. Same situation on a MILC because there is no mirror to block the light. What I read in old photography books from the 50's was to make sure the lens was not focused to infinity when carrying it around. Just like burning leaves with a magnifying glass, if focus is not correct it can't burn. So I got in the habit of always setting the focus to minimum after a shot. I would think stopping down would make things worse because now you have a greater depth of field and you're more likely to focus the light at the focal plane.

I actually hadn't thought about this as it applies to MILCs until I read your post. Maybe I'll get back in the habit of changing the focus after a shot.

Last edited by post_eos; 01-05-2013 at 12:49 AM.
01-05-2013, 02:09 AM - 1 Like   #4
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QuoteOriginally posted by cristigj Quote
the camera seems to stop it down at shut-down and as the light changes even if I have it set in manual mode.
Also, the K-01 will often automatically stop down the lens from a selected wide aperture during live view, only to open it up again once you take the shot.

01-05-2013, 03:40 AM - 1 Like   #5
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Yeah, the M mount that will work w/o vignetting on the K-01 is probably going to be the $2995 cine 50mm t0.95 m mount, not the micro 4/3s mount. The glass cut/size will (should) be different. Ask them to send you comparison shots of the two lenses side-by-side.
01-05-2013, 11:24 AM - 1 Like   #6
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In MF days before computer lens design, typically f/1.4 lenses were not as sharp in mid-range apertures as the f/1.7 lenses (as is clearly true with the Pentax m series). When you have more glass, the critical tolerances are greater. With the modern lenses, this isn't a major factor. However, you have issues such as focus shift (especially true in a longer lens such as 85mm). When you have superb integrated fast lenses from Pentax, Sigma and Samyang (Rokinon, et.al.), I'd hesitate to look at any lens requiring an adapter which introduces concerns about integrity, durability and assembly tolerances.

Keep in mind, as you go beyond f/2 sensor light fall-off becomes ever-more severe. Light gathering going beyond f/1.4 is subject to very significant drop off (depending on sensor construction). See:

DxOMark - F-stop blues
01-05-2013, 09:13 PM   #7
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To PostEOS -- thanks for the tip on opening up the aperture and making sure i am not focused to infinity. The sensor issue is obviously of concern. I have read of people burning holes in the shutter-screens of their rangefinders. No thank you!

To jatrax -- thank you for the info on flange adaptation. It seemed like these lenses were being marketed to micro four-thirds mirrorless cameras in particular. However, I know that there was a k to q adapter out there for the pentax, and I was unsure of the direction (k to q or vice versa) and if there are corrective optics involved. Also, if you check out Huff's post, he seems to be saying that the Leica M mount is a more-or-less universal mount...I dont know, that's how i understood the gist of what he was saying, and I have seen something called a Leitax adapter. Thank you for clarifying this.

To ScooterMaxi Jim -- thanks for the tip on the DxO website. I have been skeptical about these really fast lenses for a number of reasons, the price-tag being chief among them. yeah, it might be cool to be able to shoot hand-held wide open at dusk with available light, but is that really two-to-ten-grand-worth of coolness? This adds another reason to be skeptical, I suppose. Like I said, the fastest lens I have worked with (granted I have only been working with my new digs for about a week now, before that I was using an entry level fuji point and click) is the Pentax M 50mm f/1.7 SMC. On an average day of shooting, I am in a variety of different lighting situations and I have found this lens to particularly accommodating, sharp all-around, and versatile.

The question I have about fast lenses at or around this range (0.7 - 1.0 or 1.2) is this -- why bother with diaphragm at all? If what this guy at my local shop tells me is correct -- that lenses like the NoctiLux are acknowledged by the manufacturer to be sub-par at any stop other than wide open, why bother with the aperture diaphragm? I think I just saw a Russian lens on eBay that had no diaphragm at f/1.5. Seems like it could be a way to make the lenses cheaper and more available? I dont know...

In any case, thanks for the input. This has been very educational for me.
01-05-2013, 09:42 PM   #8
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QuoteOriginally posted by cristigj Quote
Also, if you check out Huff's post, he seems to be saying that the Leica M mount is a more-or-less universal mount...I dont know, that's how i understood the gist of what he was saying,
I did read his post.
QuoteQuote:
Instead SLR Magic made it in the M mount because so many adapters are made for this mount. So this one lens can be used on almost any mirrorless system with an adapter. This was a great move IMO. For example, if I have a Fuji X camera and an OM-D and a NEX-6 or 7, this one lens can be shot on all of them. Awesome.
That is certainly true but the exact same thing can be said about Canon EF, Sony A, Pentax K, Nikon F and M42. So while what he said is true I don't think it is all that remarkable. I am sure SLR Magic had a reason to make it in M mount I'm not sure it was because of any "universal donor" idea.

Any lens with a longer flange focal length than the destination camera mount can be adapted without too much trouble. Going the other way can be done but requires corrective optics which usually introduce enough image degradation to make it not worth the effort. There are other factors involved besides the flange focal length including the diameter of the mount and maybe there is something about M mount that makes it easier to adapt. At 27.8mm it is much closer to the 19.25mm of the micro four thirds mounts so the adapter would be smaller, and maybe that is enough reason. But I cannot think of anything easier to adapt from than M42 so who knows.

01-05-2013, 10:34 PM   #9
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Two things from the Huff article - I didn't see anything calling the M mount a universal donor, just that SLR Magic picked it because there are so many adapters out there, which doesn't really make sense - there are just as many adapters for legacy SLR lenses. Probably, they picked that mount because it has a long enough register distance to work with most MILCs without having to go up to the ~45mm range of SLR lenses. Also, Huff doesn't say it can be adapted to any mirrorless system, he says "all of the popular" and "almost any". The K-01 would be the exception, since it's the only mirrorless with a legacy SLR mount, and that mount has a register distance longer than Leica-M (and sadly, "popular" is not a good word to describe the K-01). As Jatrax has said, longer-to-shorter is easy; shorter-to-longer won't be able to get infinity focus unless you can put the lens inside the body, or have additional optics that usually degrade the image.

For "most universal" mount, I'm going with Pentacon Six. Carl Zeis Jena actually listed some lenses as M42 that were just the P6 lens with a matching P6->M42 adapter.
01-06-2013, 11:02 AM   #10
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yes, perhaps I was misreading his take on why the m-mount was selected for the SLRMagic lenses. Its just I have seen some reviews of various Leica lenses in this forum's database and they reference the" Leitax " adapter (which, from what I can surmise, is a third party adapter, maybe not specifically for M-mount), I suppose I was under the impression that the M-mount was as versatile for K-mount pentax bodies as the M42 seems to be. Maybe wishful thinking on my part -- not that Leica lenses are as abundant on the used market or as cheap as legacy M42 lenses, but knowing that it could be an optional future upgrade to the lens collection is a nice thought. I am not sure, maybe the Summilux lenses reviewed in the lens database are not M-mount?

Thanks again to everyone for your insight into this and for setting me straight on this. If considering purchasing a premium lens, it is good to know what can and what cannot work.
01-06-2013, 11:25 AM   #11
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I believe the Leitax (Leica - Pentax) is for the Leica R-mount which has a 47mm flange focal length. Leica & Pentax & Nikon | Leitax The only Summilux lens I can find in the database is R-mount, not M-mount

And I don't necessary think you misread him, I think he was stretching his point a bit although in fairness the article is about mirrorless and m4/3 cameras so as I said above what he said is not untrue just not the whole story.
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