[falconeye]

@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.

Yes.

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.

You said it right in your first paragraph but don't deduce the logical implication from it.

There really must be a counter-intuitive thing in there. So again: the crop factor does not help keeping the lens size or weight down for a telephoto lens at equivalent magnification.

For a given field of view, shutter speed and image quality, the size of the sensor does not affect the required lens diameter in mm, nor its weight, size or cost (see above for arguments).

Of course, there ARE bigger lenses for bigger sensors at a higher cost. But they deliver a correspondingly better IQ.


Maybe, an example helps:

Assume the DA* 200mm f/2.8 be an APS-C only lens and the DA* 300mm f/4 an FF only lens (both really are APS-C and FF lenses, but that doesn't matter here).

Then the given fact is that both lenses on their respective sensors deliver images which you cannot tell apart when printed (if the pixel count is the same). And they are same size, weight and cost (roughly).

(BTW, you may find a 300mm f/2.8 where you won't find the corresponding 200mm f/2 -- but that doesn't make the FF lenses bigger as such).

[NickC]

Yes.

Maybe, an example helps:

Assume the DA* 200mm f/2.8 be an APS-C only lens and the DA* 300mm f/4 an FF only lens (both really are APS-C and FF lenses, but that doesn't matter here).

Then the given fact is that both lenses on their respective sensors deliver images which you cannot tell apart when printed (if the pixel count is the same). And they are same size, weight and cost (roughly).

In this case you can use a faster shutter speed with the APS-C camera if the lenses are used wide open.

I do understand your physics argument regarding the number of photons, and I know that f-stop hole diameter is relative to focal length, but in practical terms a 200mm f/4 lens which covers the same fov on APS-C as a 300mm f/4 lens on FF is smaller and lighter and gives the same exposure reading at the same f-stop.

Nick

[falconeye]

I do understand your physics argument regarding the number of photons

No, you don't. Or you just don't realize the implications (otherwise, you wouldn't have compared two f/4 lenses (300mm f/5.6 exists) or touched the shutter speed).

But sorry, I have to give up here. No offense intended. Just no more time to spent on the issue.

[Anastigmat]

OK, then they better get used to journalists/reviewers scaring away people with the "be careful buying these lenses because you will not be able to use them on a FF DSLR later!" argument... :ugh:

But then again, I understand that the FF project is in a very early stage and could still go down the drain if not economicaly sound, leaving Pentax exactly where it was last year: an APS-C only company with no need for FF lenses (just as Olympus is a 4/3rd only company).

The question then becomes: do I need a FF camera? But that's another story of course...

Since Samsung is making the sensor, and since it is most likely a CMOS sensor, there is no reason why it should not be economically sound. Olympus cannot go full frame because they have painted themselves into a corner with a permanently small sized sensor with no room for expansion. Olympus would have to abandon the 4/3 mount to go full frame. Doing so will leave a lot of users with obsolete and expensive lenses. Not doing so will leave themselves far behind in the race for image quality. It is going to be difficult for Olympus to get out of the 4/3 format mess they have created for themselves.

[Anastigmat]

There is a simple reason that I'm not very excited about a 'FF' Pentax DSLR. Pentax is a small company, if it builds a FF camera, that means that in all likelihood there will be no top of the food chain APS-C. In other words, if they do a pro body, and if they do 'full frame' they would be less likely to do an APS-C size pro body. That means that not all, but some (some of which I own) lenses would be incompatible, or at least less compatible than on the current system. This also means a bigger, heavier camera, and bigger heavier lenses for equivalent focal length and speed. I don't know about anyone else, but I'll take the K20D and the DA* 50-135mm over a D3 with a 70-200mm f2.8 just based on size alone. Besides that, I'm still convinced that sensor technology will continue to allow better and better images at higher ISO's from smaller and smaller sensors.
I've heard it predicted before, and I'll jump on the band wagon to support the idea, that APS-C will take the role of 35mm film in the past, and that 'FF' will take the place of smaller medium formats like 6x4.5.
I'd rather have all the pro features in the smallest possible body, and have my 400mm lens have 14mp or better resolution at an equivalent to 600mm focal length on the 'FF.'

But that's probably just me...

The D3 is about the same size as the D2X. So there is no reason to think that full frame models must be bigger than APS-C. As for sensor technology getting better, any improvements can be implemented on full frame models. So there will always be a gap between APS-C and full frame in terms of image quality. Your 400mm lens almost certainly cannot resolve enough detail to take advantage of a 14mp APS-C sensor. In fact, you are better off with a lower resolution sensor with less noise, so that you can use a higher shutter speed to eliminate camera shake and subject motion. A lower pixel count camera can actually give you a sharper image. The high pixel count APS-C cameras simply rely on heavy doses of detail smudging noise reduction to make the images appear less noisy. A better way to reduce noise is to have a stronger signal, and it is only possible if the sensor is large enough to permit larger pixels, if one also wants lots of pixels.

[Art Vandelay II]

10-14 megapixels is more than enough for me. Any more then that is just complete and total over kill since I never print larger than 11x14 on an ink jet printer. People doing magazine covers printed at 300dpi or better need the EOS 1D's of the world, but not me. I totally agree with proudtoshootpentax, when someone makes a 70-200mm f/2.8 the same size as Pentax's 50-135 then I might be interested, but until then I'll pass.

In some cases such as Nikon's DX 16-85 at 2.8x3.4" it's about the same as their FF 24-120 at 3x3.7". That minor size difference is irrelevant to me; but when you compare Pentax's 3x5.4", 575g 50-135mm to Canon's 3.4x7.8" 1407g, 70-200mm, then it's an issue. Another fine example is Pentax's 3.3x3.9 16-50mm, 565g to Canon's 3.3x 4.9", 950g 24-70 F/2.8. If you get enough of those in your bag it add's up real quick.

Plus there's the fact that I have never seen a high quality 300mm lens cheaper then a 200mm lens. This is not a perfect example, but take a look at Nikon's 200mm f/2.8. You can get it for $800. However, their 300mm f/4 is $1100+. I personally would much rather have the 200mm f/2.8 on an APS-C body then a slower 300mm on a FF body.

[Confused]

Hi Anastigmat

Re your statement:

Olympus cannot go full frame because they have painted themselves into a corner with a permanently small sized sensor with no room for expansion. Olympus would have to abandon the 4/3 mount to go full frame.

Although I am in general agreement with your sentiments above, past experience has shown that where commercial organisations are concerned, no such concept as cannot exists ! Obviously as far as I am aware, Olympus presently have no immediate plans to enter into the full-frame arena, but where I beg to differ with you is when you said:

Doing so (abandoning the 4/3 mount) will leave a lot of users with obsolete and expensive lenses.

...which is PRECISELY what Olympus infamously did a decade or so ago (without the slightest compunction) to their die-hard band of loyal followers, when they ditched the 35mm OM-bayonet lens-mount ! I can personally attest to this treachery, because unfortunately I was one of those adherents !!!! So if you seriously believe that Olympus would never ditch the 4/3rds mount at some time in the future, I fear you may well be mistaken. Naturally for the sake of all current Olympus 4/3rds DSLR users out there, I hope that the 'status quo' remains, but NEVER say never......you have officially been warned !!!

Best regards
Richard

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Last edited by Confused; 05-12-2008 at 12:00 PM.

[WendyB]

<<...which is PRECISELY what Olympus infamously did a decade or so ago (without the slightest compunction) to their die-hard band of loyal followers, when they ditched the 35mm OM-bayonet lens-mount ! I can personally attest to this treachery, because unfortunately I was one of those adherents !!!! So if you seriously believe that Olympus would never ditch the 4/3rds mount at some time in the future, I fear you may well be mistaken. Naturally for the sake of all current Olympus 4/3rds DSLR users out there, I hope that the 'status quo' remains, but NEVER say never......you have officially been warned !!!>>

Richard is spot on on this one, plus may I add Olys disconcerting extremely long wait for the E-1 replacement. With not such innovation as was expected. I agree Oly will dump the 4/3rds to remain competitive and care none the less about it. Caveat Emptor.

Meanwhile Pentax moves "FORWARD" with fresh and practical innovation and ** (edited) in the very near future.

Try 6:45am on 17th of a beautiful fall day.

[Canada_Rockies]

Hi Anastigmat

Re your statement:



Although I am in general agreement with your sentiments above, past experience has shown that where commercial organisations are concerned, no such concept as cannot exists ! Obviously as far as I am aware, Olympus presently have no immediate plans to enter into the full-frame arena, but where I beg to differ with you is when you said:



...which is PRECISELY what Olympus infamously did a decade or so ago (without the slightest compunction) to their die-hard band of loyal followers, when they ditched the 35mm OM-bayonet lens-mount ! I can personally attest to this treachery, because unfortunately I was one of those adherents !!!! So if you seriously believe that Olympus would never ditch the 4/3rds mount at some time in the future, I fear you may well be mistaken. Naturally for the sake of all current Olympus 4/3rds DSLR users out there, I hope that the 'status quo' remains, but NEVER say never......you have officially been warned !!!

Best regards
Richard

Olympus was not the only company to completely change lens mounts to the disadvantage of their users. Minolta did the same thing when they went AF, as did Canon. I have a friend who had roughly US$6,000 in Minolta D mount equipment that was obsoleted overnight. Was he happy? I think not. My ears are still ringing.

[ftpaddict]

I have a feeling that not too long from now, someone will come up with a breakthrough sensor design that eliminates most, if not ALL noise, without compromising image quality.

Suddenly, the Olympus alternative doesn't look so bad, does it?

[Matjazz]

Suddenly, the Olympus alternative doesn't look so bad, does it?

The Oly alternative doesn't look so bad even as we speak. I doubt they will change 4/3 anytime soon because jumping ship wouldn't cost much more than upgrading existing lenses and I doubt they can afford that at the moment.

[ftpaddict]

The Oly alternative doesn't look so bad even as we speak. I doubt they will change 4/3 anytime soon because jumping ship wouldn't cost much more than upgrading existing lenses and I doubt they can afford that at the moment.

Oh most definitely. I had the chance to play with an E-410 this weekend. Saw live view on a DSLR for the first time. Reminded me of the time I used to use an Optio S...

It's small and a bit uncomfy without the grip, but ISO 400 is clean enough and the lenses are awesome.

[falconeye]

a breakthrough sensor design that eliminates most, if not ALL noise, without compromising image quality.

Many people feel like this. Therefore, it may be interesting to point to the reason why this cannot happen:

The source of noise (its biggest component, actually) is the flux of photons itself which is random (with Poisson distribution) by the fundamental nature of quantum physics. Nothing anybody could do about. Before this, we travel faster than the speed of light

There is still room for improvement though: Higher quantum efficiency, higher electron capacity per cell, higher photon to electron conversion rate, lower (no) readout noise, no loss due to color filters, to name the most important ones. Maybe, alltogether a good factor but limited by the "perfect" sensor, maybe a factor of 10 away. But this improvement is independent of the sensor size.

So, the difference between sensor sizes will stay. Unfortunately.

[Matjazz]

So, the difference between sensor sizes will stay. Unfortunately.

Definitely. As well as there will always be a difference between the sound of audio CD and super audio CD (SACD), but can you hear it?

[proudtoshootpentax]

Definitely. As well as there will always be a difference between the sound of audio CD and super audio CD (SACD), but can you hear it?

That's the critical question for me... or in this case can you see it? Pentax claims that currently the new sensor's pixels use 40% if their area to gather light. I would say that's room for improvement right there (I know there's a lens in front of each one which also helps). I'm sticking to my belief that in a few years APS-C will come so close to what FF is today that you won't be able to tell the difference. Yes, FF will still continue to get better, but there will come a point when APS-C will more than fill the needs of most people. If you still need more improvement, then perfect the foveon sensor, or Fuji's super pixel sensor. (I'd love to see the latter in a Pentax pro body) There will always be some advantages to FF, but there will always also be some advantages to APS-C, and I think it's been shown that APS-C is capable of producing some incredibly professional looking images.