[Pål Jensen]

Obviously, shorter the focal length the harder it gets (because of the register), so a 30/1.0 is not possible even on EF, let alone PK.

Somebody correct me if I'm wrong (just learned about this principle recently ;-)

I thought it was only the diametre of the lens mount that was the limitation. I could be wrong....

[jeffkrol]

I thought it was only the diametre of the lens mount that was the limitation. I could be wrong....

Canon supposedly made their lens diameter bigger just to accommodate a particular fast lens (50mm f1.0 I believe), so mount dia does play out here. Now registration distance is not, as far as I am aware, critical here. BTW: Any mm lens shorter than registration distance has to be designed as a retrofocus lens...
Wide-angle lens - Wikipedia, the free encyclopedia

[Douglas_of_Sweden]

Let's hope you are right!

[vietlh81]

It won't cost that much. This is one of the advantages of APS-C format; lenses are cheaper to make as they don't need to cover as large image circle. It believe that Pentax should take all the advantages the smaller format gives. They have done that with the DA Limites which are ultra compact.
My guesstimate is that a DA* 30/1.0 could sell in the $1000 brice brackett give or take a few....

I think that $1000 is impossible. The 60-250 F4 (with the incredible price ~ $1500) is more expensive than the Canon 70-200 f2.8 L USM.

To produce the wide angle lens (<35mm) is more difficult than 50mm. Have you ever seen the 35mm f1.2 for SLR?

[jeffkrol]

I think that $1000 is impossible. The 60-250 F4 (with the incredible price ~ $1500) is more expensive than the Canon 70-200 f2.8 L USM.

To produce the wide angle lens (<35mm) is more difficult than 50mm. Have you ever seen the 35mm f1.2 for SLR?

Where do you guys get these great prices from????
Canon EF 70-200mm f/2.8L IS USM Telephoto Zoom Lens for Canon SLR Cameras
Other products by Canon | See collection
List Price: $1,999.00
Price: $1,599.00
You Save: $400.00 (20%)
http://www.amazon.com/Canon-70-200mm-2-8L-Telephoto-Cameras/dp/B00006I53X
OK, I see I did the IS version:
Canon EF 70-200mm f/2.8L USM Telephoto Zoom Lens for Canon SLR Cameras

List Price: $1,900.00
$1199.99
And in going to f/4

Canon EF 70-200mm f/4L USM Telephoto Zoom Lens for Canon SLR Cameras
List Price: $970.00
Price: $639.00
Pentax:
Pentax SMC DA* 60-250mm f/4 ED IF SDM Telephoto Zoom Lens w/ Case for Pentax Digital SLR Cameras

List Price: $1,499.95
Price: $1,442.88
Keeping that close to list just tells me to wait to buy...
Going below $1000 may be tough but without any quality comparisons between th Canon and Pentax f/4 there is no way of knowing if one is overpriced...
and of course you have the greater zoom range.... arrgggg.

[vietlh81]

I mean Canon L USM,
not L IS USM ;-)

[Pål Jensen]

Canon supposedly made their lens diameter bigger just to accommodate a particular fast lens (50mm f1.0 I believe), so mount dia does play out here. Now registration distance is not, as far as I am aware, critical here. BTW: Any mm lens shorter than registration distance has to be designed as a retrofocus lens...
Wide-angle lens - Wikipedia, the free encyclopedia

How do you calculate the front diameter for such a retro focus wide-angle lens; ie the 30/1.0?

[sezme]

How about this for K and M lenses then: you set the maximum aperture (e.g. f/2.8), then you set the F number on the dial (e.g. f/8), and voilà: Av mode with open-aperture metering for M and K lenses.

This would explain how F 1.0 could be displayed on the LCD panel in that K-7 photo, although I doubt that it's likely.

[ryan s]

I think that lens would be:

Huge
Expensive
Extremely hard to use
Prone to all sorts of abberations

Not gonna happen.

How about this for K and M lenses then: you set the maximum aperture (e.g. f/2.8), then you set the F number on the dial (e.g. f/8), and voilà: Av mode with open-aperture metering for M and K lenses.

This would explain how F 1.0 could be displayed on the LCD panel in that K-7 photo, although I doubt that it's likely.

IMO they tinkered with the firmware to get f/1. If they would implement the rest of your plan...words cannot describe the awesomeness

[Art Vandelay II]

Where do you guys get these great prices from????

It's really hard to beat Canon on lens pricing. Plus their range is so vast; aside from pancake primes they have everything covered. If IS isn't important to you it's hard to outdo them. I've often wondered how Sony can ask $1800 for their 70-200mm f/2.8 when Canon's non-IS 70-200 f/2.8 is every bit as nice and only $1100. Pentax asking $1500 for the f/4 60-250mm while the non-IS Canon 70-200mm f/4 is only $600 is equally as troubling. I understand Pentax asking maybe $1000 for it, but $1500 is over the top.

[eurostar]

Pentax 60-250 is a 4,1x zoom compared to the Canon 70-200 2,8x. It' quite a difference.

[Steelski]

A few points. Why would Pentax deliberately go out of their way to include a F1.0 setting when all previous Pentax SLR cameras only went to F1.2
And the 50mm 1.2 lenses were of a reasonable size.
And whoever said the Nikon G 1.4 50 lens is as good as the Pentax needs to get their eyes tested I think. The lens is not sealed and not as contrasty and sharp wide open.
If F1.0 is known to be impossible on K mount then why would it be included in the latest camera.........
This alone indicates to me that it is somehow possible but not practical yet. but who knows. F1.1???? We know the f.1.2 lenses were very compact from Pentax. Only sporting a front diameter of 52mm. The rear element was huge, though. But for a smaller sensor it may be possible.

[Art Vandelay II]

Pentax 60-250 is a 4,1x zoom compared to the Canon 70-200 2,8x. It' quite a difference.

On a spec sheet perhaps, but in reality there are very few shots you could get with the Pentax 60-250 that you couldn't get with the 70-200. Like I said, I can understand charging a few hundred more for the bit of extra range, but not 2.5x more.

[RawheaD]

Canon supposedly made their lens diameter bigger just to accommodate a particular fast lens (50mm f1.0 I believe), so mount dia does play out here. Now registration distance is not, as far as I am aware, critical here. BTW: Any mm lens shorter than registration distance has to be designed as a retrofocus lens...
Wide-angle lens - Wikipedia, the free encyclopedia

If the only thing that matters is the mount diameter, then how do you explain the Noctilux, which is f0.95 on a Leica M-mount with just 44mm mount diameter? The mount diameter for PK is 45mm, and EF is 51.2mm. No, I'm quite certain register distance plays a role, since in very basic terms, f = F/D [edited: had this reversed] where D = diameter and F = focal length. In case of cameras, the D can't be larger than the mount diameter and the F can't be shorter than the register (or something very close to those numbers).

Hence you need a mount that has a shorter register than mount diameter. For SLRs, Canon EF is the only one, with a 44mm register and 51.2mm mount diamter.

Nikon F: 46.5mm/44mm
Pentax K: 45.5mm/45mm

etc.

The Notctilux exists because of Leica M's very short register, which makes it easier to make super fast lenses (ergo, C-mount cine lenses, with super duper short registers).

[jeffkrol]

I think that lens would be:

Huge
Expensive
Extremely hard to use
Prone to all sorts of abberations

And soft
Some facts and history of the 50mm f1.0 and why it may really not be necessary:
That's the Canon 50mm f1.0 lesson...: Open Talk Forum: Digital Photography Review
john p vansteenberg wrote:
> It has little or nothing to do with mount diameter. That impacts
> target size. Business end of aperture happens far in front of the
> mount. (But, it is true that small target sensors make the physical
> size of fast lenses relatively smaller.)

Indeed.

Canon, Nikon, Minolta, Pentax, etc. were all making f1.2 lenses for their respective systems.

Canon had to go all the way up to f1.0 before they found a lens that really wouldn't fit existing mounts. The did that several decades ago with their 50mm f0.95 for rangefinders: a complex double lens mount that surrounded a conventional rangefinder mount with a larger outer mount only for the 50mm f0.95. Then they did it again with EOS, making the new mount large enough to handle a 50mm f1.0 SLR lens.
> It does have to do with the practical problems of lenses:
> 1. Size, weight, price.
> 2. Flare, abbrrations and other image degradation issues.

Both of those things really worked against the Canon 50mm f0.95 and 1.0

> and most importantly....
> 3. Who need one? (also known as "how many can we sell?"). With ISOs
> getting so high without noise, 'ALMOST NOBODY' is the markets'
> answer.

That's another lesson Canon learned with the 50mm f1.0. By the mid 80s, film had gotten so good that there was little demand for the 50mm f1.0. A half stop advantage over a 50mm f1.2 wasn't worth the flare and softness, or the size, weight, and cost.

My sources say there was just one production run, and it took Canon 15 years to clear them all out of the warehouse.
> Then management asks: "How much will it cost to develop and
> how will we have to price it to make some money on it?"
>
> When the answer is calculated the facts often become clear: the price
> will be very high or the rest of the items in the lineup would have
> to subsidize the cost to keep it down.
>
> Therefore, usually, the perceived brand value of offering such
> products loose out to the practical limitations of the market.

Yes. Unless it's a "halo product". Canon loves to pride themselves on being the company with unique products...

How do you calculate the front diameter for such a retro focus wide-angle lens; ie the 30/1.0?

Don't know