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05-15-2009, 04:56 PM   #46
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QuoteOriginally posted by robjmitchell Quote
F/1.0 is the same as the EXIF info you get any time you use a non A lens, like an old Takumar! no mystery to me.

No. EXIF says f/0.0 on my camera. The mystery persist....

05-15-2009, 05:01 PM   #47
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QuoteOriginally posted by cousinsane Quote
DA30/1.4 sounds more realistic to me. But then again, it probably wont be cheap and will compete with FA30/1.8. Personally I'd rather see pentax make a DA24/2, which is a very very useful focal length on APS.
Agree about the DA 30/1.4. However, the APS system opens oportunity of making fast lenses not achieveable or not realistic for FF. Just like it opens up opportunities for super compact lenses, like some of the Limiteds. I believe Pentax should take advantage of that for marketing the advantage of the APS system.
The DA 30 is a mystery anyway; not exactly the lens Pentax needs the most unless it is something special. We already have the 31/1.8, 35/2.8, 35/2 and various zooms that covers the same focal lenght.

A DA 30/1.4 should be comparable in cost to the 31/1.8 Limited. After all, it doesn't have to cover such a large image circle.
05-15-2009, 05:08 PM   #48
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QuoteOriginally posted by jogiba Quote
I don't think a 30mm F1.0 for the APS-C sensor would be any larger than the Pentax 50mm F1.2 for a FF sensor IMHO.
Sizewise I would guestimate it between the size off the Pentax 35/1.4 (anyone got one of those?) and the A* 85/1.4.
05-15-2009, 05:09 PM   #49
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This thread is spinning fast ...

QuoteOriginally posted by RawheaD Quote
I think it is physically impossible to make a 30/1.0 lens for a PK mount camera, irregardless of how big you make the primary element. I think it's impossible to make a 50/1.0 lens for a PK mount camera. The register is too long (and the mount opening is too narrow).
I wanted to say something similiar. BTW, the K mount was specified to accomodate a 50/1.2 lens which wasn't possible with M42 screw mount

Lenses in the range f/0.8 .. f/1.2 are hard to design in a way that they are sharp wide open. Basically, you need a focal length very similiar to the distance of entrance pupil and focal plane. So, with a k mount registration distance of 45.46mm, focal lengths in the order of 50mm are ideal to make a f/1.0 lens. Longer makes the opening hole too narrow, shorter makes the construction too complex.

Lenses in the range f/0.8 .. f/1.2 are commonplace ... in microscopy and focal lenght are very short. I don't remember exactly. Something like 1mm ...

05-15-2009, 05:14 PM   #50
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QuoteOriginally posted by falconeye Quote
This thread is spinning fast ...



I wanted to say something similiar. BTW, the K mount was specified to accomodate a 50/1.2 lens which wasn't possible with M42 screw mount

Lenses in the range f/0.8 .. f/1.2 are hard to design in a way that they are sharp wide open. Basically, you need a focal length very similiar to the distance of entrance pupil and focal plane. So, with a k mount registration distance of 45.46mm, focal lengths in the order of 50mm are ideal to make a f/1.0 lens. Longer makes the opening hole too narrow, shorter makes the construction too complex.

Lenses in the range f/0.8 .. f/1.2 are commonplace ... in microscopy and focal lenght are very short. I don't remember exactly. Something like 1mm ...
That sucks...
Oh well....
05-15-2009, 05:41 PM   #51
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QuoteOriginally posted by Art Vandelay II Quote
These studio tests are great and all, and in ideal conditions when mounted on a tripod yes the Pentax 55mm looks better at 1.4, but in real world shots with a moving subject I seriously doubt anyone would notice the slightest difference unless you are either doing some serious pixel peeping or making extremely large prints. Focus mistakes will come into play more then lens flaws.

Besides, the point was not which lens is better, it was that both have about the same specs, similar build quality, similar results, similar release dates, but Pentax has chosen to charge $200 more for theirs.

These companies are just very inconstant across the board. It's odd. Here is an example in Pentax's favor comparing prices between the Pentax 16-50mm 2.8 and the Nikon 17-55mm 2.8. The Pentax lens is $500 cheaper!
Yes, No, Maybe.

Yes the difference is not massive, But there is a difference, that difference cost more money to build IMO.
I love printing big.
I often crop. Having an extremely sharp lens at max aperture is useful when printing even A4 when you crop.
Sometimes static subjects need 1.4 also or studio portraits. Being able to see every fiber/pore/wrinkle is very nice.
I can not afford it at the moment, But I hope to be able to in the next year.
The 16-50 is a running joke for Pentaxians. One minute its praised, the next it can not focus and looks fuzzy down the side. I so wish they would bring out a version II of that lens at the same price. Same for the 50-135, the motors burn out. The rest of our DA* line is a shining example of what Pentax is capable optically and mechanically.

Anyway, back to my point. Simply put I think the lens is almost worth its money. Not so for the Nikon, the Sigma smokes it!!! Now, Pentax vs Sigma in K mount.....
Anyway again, I think if Nikon made a lens as good as the Pentax they would be able to charge the extra money, but they did not in this instance.
We do not even know how much the cost to make these lenses is. If Pentax made a lens from better parts to increase performance then they should charge more. But we do not know really. Now I am off to bed..... Nice chatting.
05-15-2009, 05:46 PM   #52
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Here's the photo. The camera is in manual mode and someone dialed this in. So basically, the camera is some sort of prototype where you can dial in anything or it has a lens mounted that have a max aperture of F:1.0.
Or it is a photoshop job
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05-15-2009, 05:57 PM   #53
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I'll point out to you guys that Voigtlander make a 35mm f/1.2 which is a bit bigger than the 31mm f/1.8 limited but that is hardly an issue, so I'd say that physically yes, it is possible.

it's just a question of whether the lens mount could handle such an extreme lens design. because the exit pupil has to be a certain size to obtain the proper illumination at the image plane without suffering from light fall off.


though it just occurred to me that they could get around the lens mount limitation by making it as DA lens...if there is a will there is a way....


Last edited by Digitalis; 05-15-2009 at 06:03 PM.
05-15-2009, 05:59 PM   #54
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Or the prototype LCD is hooped, and it should read F11.0...
05-15-2009, 06:15 PM   #55
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QuoteOriginally posted by Pål Jensen Quote
Here's the photo. The camera is in manual mode and someone dialed this in. So basically, the camera is some sort of prototype where you can dial in anything or it has a lens mounted that have a max aperture of F:1.0.
Or it is a photoshop job
Just noticed and a bit OT but, only +2/-2 EV ?
05-15-2009, 06:27 PM   #56
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QuoteOriginally posted by ajuett Quote
Just noticed and a bit OT but, only +2/-2 EV ?
I'm hoping the VF will show at least a +3/-3, ideally a +5/-5. Perhaps +2/-2 on the top LCD is just due to a lack of space because of the K7's compact size?
05-15-2009, 06:39 PM   #57
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QuoteOriginally posted by Art Vandelay II Quote
I'm hoping the VF will show at least a +3/-3, ideally a +5/-5. Perhaps +2/-2 on the top LCD is just due to a lack of space because of the K7's compact size?
If space was a concern they could simply display '-3.5' instead of a whole bar that takes up room.
05-15-2009, 06:40 PM   #58
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QuoteOriginally posted by ajuett Quote
Just noticed and a bit OT but, only +2/-2 EV ?
Didn't somebody already clarify that the available +/-EV range depends on the setting of aperture steps, if 1/2 or 1/3 stops?
05-15-2009, 06:44 PM   #59
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QuoteOriginally posted by falconeye Quote
Didn't somebody already clarify that the available +/-EV range depends on the setting of aperture steps, if 1/2 or 1/3 stops?
ha, hell if I know. I do a pretty good job of keeping up around here, but you'd have to work full time to follow all of the K7 threads.
05-15-2009, 06:45 PM   #60
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From the image that bar indicates 1/3 steps from -2 to +2
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