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02-10-2009, 02:49 PM   #31
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Well the new DA15 is clearly not a portrait lens and it most certainly isn't built for hunting animals either ... I guess that leaves you little categories where you'd need shallow DOF with this lens.

Going a bit OT here. I can get get pretty good results with the DA12-24 at f/4 so I guess the DA15 will behave similarly (in terms of DOF). I just hope it has nice rendering - read: contrast, sharpness, less CA than the DA12-24 etc. (yes I've seen some samples shot with the DA15 but I want to test it myself).

02-10-2009, 02:57 PM   #32
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i fail to see how the 15mm was needed,

when we have a very good quality 14mm, albiet larger in size, but faster in aperture, that receives great feedback from all users.
02-10-2009, 02:58 PM   #33
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I need it
02-10-2009, 03:01 PM   #34
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The point is with the Fuji CCD EXR technology is that it is not currently being used with anything as large as an APS-C sensor. The revised sensor pattern on an APS-C sensor would lead to an increase in performance (maybe even close or equal to a standard Bayer pattern FF sensor).

02-10-2009, 03:04 PM   #35
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QuoteOriginally posted by fejker Quote
Well the new DA15 is clearly not a portrait lens and it most certainly isn't built for hunting animals either ... I guess that leaves you little categories where you'd need shallow DOF with this lens.
these are both 16mm fisheyes on a APS-C

http://fork.zenfolio.com/img/v1/p1059792518-4.jpg

http://fork.zenfolio.com/img/v3/p601446554-4.jpg

i often run into situations where i want my wide angles to be fast, whether due to low light or wanting to pop the subject out.


this is a 28mm F1.8 on film, i would have loved for it to be even wider while maintaining depth of field (and admit enough light to take the photo)

http://fork.zenfolio.com/img/v6/p978980135-5.jpg
02-10-2009, 03:15 PM   #36
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I agree with you Gooshin, sometimes you would need that f/1.2 ... but imagine a lens that wide and that open that covers FF.

The DA15 will probably be my choice and replace the DA12-24 in my bag.

In most cases I need more DOF:
http://www.fejker.net/wp-content/uploads/2009/02/imgp4302.jpg
http://www.fejker.net/wp-content/uploads/2009/01/imgp7372.jpg
http://www.fejker.net/wp-content/uploads/2009/01/imgp9187-800.jpg
http://www.fejker.net/wp-content/uploads/2008/08/imgp9332.jpg
http://www.fejker.net/wp-content/uploads/2008/06/imgp6535.jpg

Well, not always (this one is with the DA12-24 wide open):
http://www.fejker.net/wp-content/uploads/2008/07/imgp7354.jpg
02-10-2009, 03:28 PM   #37
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this is where the whole full frame desire comes in.

lenses exist already, in the full frame world, that can give me what i want

take the FA20 F2.8, that thing is not large at all, but would require a 13mm f2.0 digital lens for equivelancy, it wont be made

as Samsungian mentioned, Tamron 14mm, Pentax SMC 15mm, these lenses existed for full frame, you wont see a 10mm f2.0 rectaliniear lens made for APS-C just yet.

FA Limited 31 F1.8

there is no current digital pentax equivalent of this (would have to be like be like 20mm f1.4 or something)

this is where the frustration and sadness comes in.

what was possible before, is no longer possible, until either pentax makes a FF camera, or the lens engineers start comming up with some really fancy stuff

this is partially where my "this lens is boring" comment came from

building a 15mm digital only F4 lens is not a big feat.
02-10-2009, 03:30 PM   #38
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As far as cost goes, we would need an engineer to explain why, but why would a ff sensor be so much more to manufacture? assuming the majority of the design work went into how to cram as many pixles into a given area(photosite density) maintaining the same photosite density, but increasing the sensor area sounds reletively simple. How much does it cost to produce one sensor? if the new one is 50%larger does cost go up by 50%?

02-10-2009, 03:43 PM   #39
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QuoteOriginally posted by shuie Quote
As far as cost goes, we would need an engineer to explain why, but why would a ff sensor be so much more to manufacture? assuming the majority of the design work went into how to cram as many pixles into a given area(photosite density) maintaining the same photosite density, but increasing the sensor area sounds reletively simple. How much does it cost to produce one sensor? if the new one is 50%larger does cost go up by 50%?
its not so much the cost per sensor

its the rate of faulty silicone slabs

which as far as i know goes up something like exponentially proportional to area

think about it, if someone gave you a pencil, and asked you to draw a perfect circle free hand, and the circle had to be an inch in diamater, what would be your success rate compared to drawing a perfect free hand circle that is 5 inches in diamater?

now imagine you get 1 page per try, and each page costs a dollar

the cost is high because you throw away alot of the faulty ones, not so much because you're making it bigger.

atleast thats how i understand silicone slab technology.
02-10-2009, 03:51 PM   #40
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I don't really understand the silicone slab theory. When making silicone microchips the actual slab is about 20 inches in diameter dozens of copies of the chips are made on each slice of silicone and then seperated. the first step in chip manufacturing is growing the pure silicone crystals. (got to love the science channel) I suppose there could be more flaws than I realize. Oddly enough normally what makes electronic components more expensive is making them smaller, not making them bigger.
02-10-2009, 04:01 PM   #41
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QuoteOriginally posted by Gooshin Quote
there is no current digital pentax equivalent of this (would have to be like be like 20mm f1.4 or something)
this is where the frustration and sadness comes in.
That's because it's very hard to make UWA lenses for APS-C sensors, but you get free 50% zoom capability with them. Your best bet is a dual system for now if it frustrates you that much (and you get tired of your MZ-S :-)

Shuie: cost is more than 50% for 50% size increase. Picture an 8" slab of silicon. Picture someone sneezing on it. You'll have more non-sneezed on chips than if you had cut large chips out of that slab, so you might be able to get 20 small chips that are ok vs. maybe 2. The "sneeze" is manufacturing impurities or defects. The cost of the 8" slab/wafer is the same so it's a matter of how many chips you get out of it. Costs also go up the smaller you make the stuff on it (fabs charge more based on feature size...smaller is more expensive). I used to do chip design in my 2nd career.
02-10-2009, 04:19 PM   #42
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QuoteOriginally posted by shuie Quote
I don't really understand the silicone slab theory. When making silicone microchips the actual slab is about 20 inches in diameter dozens of copies of the chips are made on each slice of silicone and then seperated. the first step in chip manufacturing is growing the pure silicone crystals. (got to love the science channel) I suppose there could be more flaws than I realize. Oddly enough normally what makes electronic components more expensive is making them smaller, not making them bigger.
I just know some numbers from semiconductor industry (Intel etc.), but as CMOS for sensors shouldn't be much different from CMOS for CPUs and DRAMs, it should be more or less compareable.

What they have nowadays are 12'' waver. The costs for one waver are more or less the same, thus the more chips you get out of it, the lower the costs. Thus the costs of one chip is proportional to its area. Another effect is the probability of defects. They have a certain average number of defects per waver. You can calculate how many squares of a certain size in a circle with radius 6'' are lost, assuming a certain number of dust particles on the waver. If that number is small enough, the probability to loose one chip is proportional to its area as well. In the end costs are proportional to the square of area. Having a sensor which is 1.5*1.5=2.25 times larger than APS-C means that the costs are about 5 times as much.

coon
02-10-2009, 04:23 PM   #43
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After reading the reply I was about to make I realized I was straying way off topic. I guess what I intended with this thread was the possibility of a FF camera that worked with all lenses as the lenses were designed to be used. I felt that using a higher mp ff sensor would have the added benefit of a better image in cropped mode. My whole reasonong behind this was to say pentax could still go ff and not worry about losing compatability with their aps-c lenses
02-10-2009, 04:32 PM   #44
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QuoteOriginally posted by kenyee Quote
That's because it's very hard to make UWA lenses for but you get free 50% zoom capability with them.

you get a free crop


for now why not give us more D FA lenses? that design for both sensors.
also why stop making the fa lenses?
I know that nikon and canon people with a crop fame lenses have the same problem as us but at least they have the choice to buy FF lenses as well.
re make the fa* or make a D FA * thing
both sigma and tamron selling fast lenses designed for Digital and FF for less then $400.

at the end most Slr users choosing the camera based on the lenses they are already own unless you are a first timer.

how many times I heard people telling me "I would switch to Pentax in a heart bit if I did not have all these Nikon lenses".

first thing people will tell that is bad about Pentax is availability of lenses. we have the best primes around and by far the worst zooms. if the market will go FF we will be in trouble in 5 years maybe less

Last edited by redpigeons; 02-10-2009 at 04:41 PM.
02-10-2009, 05:19 PM   #45
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QuoteOriginally posted by Gooshin Quote
think about it, if someone gave you a pencil, and asked you to draw a perfect circle free hand, and the circle had to be an inch in diamater, what would be your success rate compared to drawing a perfect free hand circle that is 5 inches in diamater?.
Actually I have a very neat trick for those situations!

Put a pen between your fingers, as you would normally do when writing, then put the joint of your "little finger" on the piece of paper, then lower the point of the pen to the base of the paper, and slowly turn the paper with your other hand while itīs pinned down by your "little finger" - voila! a perfect circle.


Unfortunately I donīt think this information tranfers to making image sensors though.
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