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05-06-2008, 11:32 AM   #106
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QuoteOriginally posted by anomaly Quote
What about the laws of economics then?
That's not my field of expertise.

05-06-2008, 12:54 PM   #107
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It's fine if they do come out with a FF body, but man I hope APS-C doesn't go away. And this is a recent change of heart for me. Until recently I wanted a FF camera, but just last week I went and looked at Canon's 24-70 f/2.8L and Nikon's 70-200 f/2.8 then compared them to Pentax's 16-50 and 50-135mm f/2.8 and it dawned on me that I have absolutely no desire what so ever to carry around those big ass FF lenses when I can get pretty much the same result either at 8x10 or even 11x14 printing from a APS-C source.

It's cool if Pentax want's to go after that niche that either wants FF or thinks they need it; but I hope they don't ever drop cropped sensor bodies/lenses for us lowly amateurs.
05-06-2008, 02:07 PM   #108
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QuoteOriginally posted by Art Vandelay II Quote
those big ass FF lenses
This is a common misperception.

FF bodies or lenses aren't bigger because they are FF. They may have been made for a market buying big, though.

First, there is absolutely no reason why an FF body shoudn't be as compact as the MX (or the *istD at least). Even with SR.

Second, tele lenses are big by diameter, not length. Same diameter, same weight, same light, same image quality. Only if you actually want to buy the extra light possible with FF will you need bigger and more expensive glass.

Third, wide angle are big by construction to capture an angle, making that 12mm APS-C and 18mmm FF roughly have the same size.

BTW, same myth goes for Depth of Field. But let me stop here

P.S.
I don't say FF or APS-C is better or not. Just want to clarify some points.

Personally, I want a digital MX, small, small glass, 35mm.
05-06-2008, 04:49 PM   #109
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I know a guy who bought a sigma 24-70 (I think it was) because it had an 82mm front filter. He chose the lens that was the biggest for the zoom range because "it makes me look professional" . Plenty of people out there think big less = good lens In my ignorance I sometimes wonder whether this gets built into design specs by some manufacturers when I look at the distance between the actual glass and the front filter threads

05-06-2008, 05:02 PM   #110
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QuoteOriginally posted by falconeye Quote
This is a common misperception.

FF bodies or lenses aren't bigger because they are FF. They may have been made for a market buying big, though.

First, there is absolutely no reason why an FF body shoudn't be as compact as the MX (or the *istD at least). Even with SR.

Second, tele lenses are big by diameter, not length. Same diameter, same weight, same light, same image quality. Only if you actually want to buy the extra light possible with FF will you need bigger and more expensive glass.

Third, wide angle are big by construction to capture an angle, making that 12mm APS-C and 18mmm FF roughly have the same size.

BTW, same myth goes for Depth of Field. But let me stop here

P.S.
I don't say FF or APS-C is better or not. Just want to clarify some points.

Personally, I want a digital MX, small, small glass, 35mm.

So why cant I make a 645 camera the same size as a 35mm camera?
05-06-2008, 08:49 PM   #111
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Not so fast...

QuoteOriginally posted by falconeye Quote
Second, tele lenses are big by diameter, not length. Same diameter, same weight, same light, same image quality. Only if you actually want to buy the extra light possible with FF will you need bigger and more expensive glass.
I just rode a bicycle 1/4 mile uphill to catch some shots for a school assignment with my 400mm 5.6. I don't want to imply that this is a compact or light lens by any stretch of the imagination, but it sure beats a 600mm f5.6 on a FF body. Also, my M 200mm f4 becomes a 300mm f4 by FF standards, not a big difference in size, but one I might appreciate on a long hike. When you start to add lenses up, the savings in weight becomes even more substantial! Take this same 400mm, 200mm, 50-135mm, and throw in a 21mm pancake for wide angle work. This beats the pants off a 600mm, 300mm, 80-200mm, and the closest thing in zoom range to the 21mm might be the 31mm Limited (couldn't complain there). In my eyes we went from a system that was a slight inconvenience at times - to one that is downright cumbersome. I'd like someone to weigh all that glass and see how it comes out. Don't get me wrong, I'm not ignorant of the fact that FF can have some advantages... but for me, they don't add up to enough of an advantage to have to partially rebuild a system.
05-07-2008, 08:53 AM   #112
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QuoteOriginally posted by falconeye Quote
This is a common misperception.
Personally, I want a digital MX, small, small glass, 35mm.
I'm with you on an MX size body, that's for sure. I personally want a nice digital range finder in fact, but there's no way I'm paying $5k to Lecia plus $1500 per lens to get one. As far as a switch to FF goes...I'm not worried about the size of the bodies; I know that can be controlled, the lenses are my only concern. I suppose you could carry a mix of APSC lenses for telephoto shots and a full frame lens for wide angle shots, then just shoot in a cropped mode when using the APSC lenses and FF mode when using the wide angle lens.

That said, then comes the price, an APSC sensor will always be cheaper to make then a 35mm simply due to size. That gap will close in the next decade, but I'm not sure if I would pay even $200-400 more for a 35mm camera. The only real advantage FF has for someone like me is better high iso performance. And honestly, good iso 1600 performance is fine, iso 3200 and 6400 would be nice, but i really don't need it. Plus FF cameras have yet to really impress me at those iso's. They certainly don't look good enough for me to use on anything other than simple snap shots.

The bottom line is I have printed 16x20" images from a 6 mega pixel APSC sensor using a $70 kit lens and they look fine; even close up. For pro's doing large format work such as race car haulers (something I used to do), then by all means get 40 megapixel FF or even medium format digitals; but for people like me that just enjoy doing landscape work the K20d is all the camera I could possibly need.
05-07-2008, 09:12 AM   #113
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QuoteOriginally posted by proudtoshootpentax Quote
400mm 5.6 [...] it sure beats a 600mm f5.6 on a FF body
You mean by being lighter, right? That's evident, because the 600mm has 1.5x the diameter, i.e., >2.25x the weight (and I said diameter, not aperture f-stop setting!).

What compares to a 400mm f/5.6 APS-C is a 600mm f/8.4 FF. Both give same light per exposure (and same FoV). Which means FF gives you no advantage, and no disadvantage.

To make it clearer what I said: FF gives you more options (such like bigger glass) and doesn't take away from your APS-C options (and I'm not talking about cropping an FF sensor).

05-07-2008, 09:19 AM   #114
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QuoteOriginally posted by *isteve Quote
So why cant I make a 645 camera the same size as a 35mm camera?
I never said one could.

One can actually make a digital APS-C smaller than anything in the current line-up, more in line with the smaller Olympus cameras. But nobody did.

And because nobody cared about shrinking APS-C cameras, they won't get any bigger when going FF. It's that simple.
05-07-2008, 02:23 PM   #115
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Misleading

QuoteOriginally posted by falconeye Quote
You mean by being lighter, right? That's evident, because the 600mm has 1.5x the diameter, i.e., >2.25x the weight (and I said diameter, not aperture f-stop setting!).

What compares to a 400mm f/5.6 APS-C is a 600mm f/8.4 FF. Both give same light per exposure (and same FoV). Which means FF gives you no advantage, and no disadvantage.
While in terms of physics you may be correct about the number of photons reaching the sensor, it's not true in practical terms as the shutter speed would need to increase with the f/8.4 lens as the photon density would be lower. Therefore in practical terms the 400mm f/5.6 APSC lens is equivalent to a 600mm f/5.6 FF lens.

Nick
05-07-2008, 03:05 PM   #116
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QuoteOriginally posted by NickC Quote
While in terms of physics you may be correct about the number of photons reaching the sensor, it's not true in practical terms as the shutter speed would need to increase with the f/8.4 lens as the photon density would be lower. Therefore in practical terms the 400mm f/5.6 APSC lens is equivalent to a 600mm f/5.6 FF lens.
I actually wondered if I had to be that specific in my response. I decided not and left out this little detail as I thougth one would just trust my argument

So here we go: With a larger sensor and same total light (hence smaller photon density) you have to crank up the ISO correspondingly in order to get the same image quality. This is because each sensor cell is larger and gets the same no. of photons, at the same shutter speed. My argument was entirely correct in practical terms.


Now anticipating another counter argument...

...The sensor cell may actually be the same size for FF and APS-C, with FF just having more of them (it better does, actually). But then, you scale the image obtained from FF to the no. of pixels obtained from APS-C and thereby exactly eliminate the extra noise you got by the higher ISO. Again, my argument was entirely correct in practical terms.


Maybe this time you just trust me, FF doesn't need bigger glass if you don't need better IQ.



P.S.
If terms of physics and practical terms would be any different we would still live in caves and for sure not use digital still cameras
05-07-2008, 03:30 PM   #117
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Some principal constraint

While I am in my physicist's mode

I see good arguments for both, APS-C and FF. However, I would like to comment on a common belief I tend to "feel" in many posts here, namely:
"In digital age, progress will be such that (the smaller) APS-C form factor will give us anything we are asking for anyway. Thus, it wil lreplace 35mm in the digital age."
I don't say it won't. But we must understand that we face a principal constraint here:

Noise from image sensors may still be somewhat minimized by improving the quantum efficiency (maybe by a factor 2), the electron production rate (maybe by another factor 2), the read-out (thermal) noise (a little bit). But soon we reach a limit here. The limit of counting individual photons. From that point on, technological progress won't help anymore, only size. (Of the lens, actually -- but bigger sensors allow for bigger lenses.)
05-08-2008, 12:18 PM   #118
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QuoteOriginally posted by falconeye Quote
I actually wondered if I had to be that specific in my response. I decided not and left out this little detail as I thougth one would just trust my argument

So here we go: With a larger sensor and same total light (hence smaller photon density) you have to crank up the ISO correspondingly in order to get the same image quality. This is because each sensor cell is larger and gets the same no. of photons, at the same shutter speed. My argument was entirely correct in practical terms.
Nope, don't get it. If I point my APSC DSLR, my FF DLSR, my Pentax 67, and my 5x4 wooden camera at the same scene, I use the same aperture, ISO, and shutter speed to record it. I don't need to crank up the ISO as the sensor gets smaller, nor change the shutter speed or aperture. That's practical

It's just a well really or that external meter would be useless.

Nick
05-08-2008, 02:06 PM   #119
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QuoteOriginally posted by NickC Quote
Nope, don't get it.
I can only guess where "I am loosing you"

I guess that you followed you own line of thinking rather than thinking thru my argument. Probably, it is this external meter thing which traps you.

Ok, let's give me another try then, taking your external meter into account.

As you have said, you can set the same aperture (as an f-stop, not diameter, here), ISO, and shutter speed to record an image, according to the readout of your external meter. I am with you here.

But with a FF camera, you will actually capture twice the light if you do so (the aperture is 1.5x the diameter or twice the surface and therefore collects twice as many photons out of the same vivible field of view). Because of this, the performance of an FF sensor at, say ISO400, is IDENTICAL to the performance of an APS-C sensor at ISO200. More or less by definition. BTW, by performance I mean the signal to noise ratio, or amount of visible noise in a print.

Are you still with me?

Ok, then it is clear why you can safely double the ISO settings with FF (compared to APS-C) to obtain the exact same image quality as with APS-C. And if you do this, you end up with lenses having the same diamater (in mm), hence weight and cost.

I may still have failed to explain myself. Please give me feedback if you can agree. Of course, I could be wrong but I don't think so.
05-08-2008, 02:42 PM   #120
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@NickC,
I think what Falconeye is trying to say is that you can have a 600mm lens with the same diameter objective as your 400mm lens, but it would be f8.4. Then considering the total amount of light hitting the sensor, it would be the same if you added up the square millimeters of light if you factor in the brightness per millimeter.

Not that it matters much to me in a practical sense. I would rather have a faster lens with a APS-C or FF camera. So, in this case the crop factor helps keep the lens size and weight down for a telephoto (or long) lens at an equivalent magnification.
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