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Messages - epsiloneri

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EOS Bodies / Re: Canon 5DmkIII
« on: November 02, 2010, 06:41:59 PM »
Consider a photo taken with a D3s and the same taken with a camera with a sensor with a size of 360 * 240 millimeters (with the same photosite size). There is no equivalence in directly comparing the two photos; the one taken with the camera with the larger sensor would have an absolutely stupefying technical quality. Why? Because the larger sensor gathers 100 times more light for the same exposure - almost 7 stops (6.64 to be exact), but the noise level doesn't increase proportionally with the sensor size.

I'm not very fond of this simplified argument, removing the optical system from the question, which you really can't: for your simile to work, you have to assume that both detectors use the same (10xFF) lens. Now what if you were imaging a bird that just fit onto the small FF frame. Would the image of the bird be better with the 10xFF detector? No. Sure, you would capture 100x more photons, but 99% of those photons would come from the boring forest, of no consequence for the image quality of the bird.

A detector doesn't produce an image by itself. It needs optics. The reason a FF camera has an IQ advantage over APS-C is that it is easier to produce suitable optics for FF than the equivalent for APS-C. In your example, if you put a 50/1.2 lens in front of the FF and a 500/12 lens in front of the 10xFF, they would produce equivalent images. They would collect the same number of photons. There would be no difference in IQ. But while a 500mm f/12 lens can be readily produced at home by an amateur astronomer (they actually do a bit better), you need Canon's expensive top-of-the-line L-optics to find a 50mm f/1.2 lens.

Lenses / Re: How many lenses could you mount on a 5DMkIII?
« on: October 29, 2010, 10:53:49 AM »
no matter how good a lens is physics dictate that the corners will never be as good as the centre

Are you saying it is physically impossible to construct a lens which is better in the corners than in the centre?   :P

Lenses / Re: How many lenses could you mount on a 5DMkIII?
« on: October 29, 2010, 10:48:14 AM »
You haven't considered the number of people who will upgrade from a 5DMkII for reasons other than a larger sensor, such as those moving away from the awful AF system.

I don't see how an increased pixel count nor improved AF is going to force people to update their lens collection. It's not like their current lenses would perform worse with a new camera (hopefully...). I agree that an increased pixel count doesn't add much if you're oversampling your lens resolutions, but it doesn't make the lenses worse. The only problem would be file sizes, if you insist on shooting full resolution and don't have the resources to back it up. Low S/N could be another area, unless you can bin efficiently. But let's not exaggerate those problems, it will not be a factor 2 different. It will in any case not force anyone to buy new lenses.

EOS Bodies / Re: New \
« on: October 29, 2010, 05:23:20 AM »
Tjee, 4D won't happen because in japanese and chinese it's unlucky number associated with death.

Well, the number 13 is an unlucky number in the western world, and you don't see that avoided. Except in the US... (I've been in buildings without 13:th floors, they go directly from 12 to 14. Same with some American airlines, I've heard... like seat row number 13 would be particular unlucky in case of an accident?!). Naa, I don't think number superstition is a big factor among camera buyers (and that's what counts). Who cares what it's called, anyway.

BTW , the chinese pronouncation of 5D2 is just like "invincible rabbit" , and the pronouncation of 7D for Cantonese (Hong Kong local language) is just like " much more stupid" .... just for fun

Haha, that's just too funny...

Lenses / Re: How many lenses could you mount on a 5DMkIII?
« on: October 29, 2010, 05:14:17 AM »
With rumours flying around about a 25mp+ 5DMkIII likely to see our stores next year, how many of the current lineup of Canon lenses have the resolving power to utilise such a large sensor?

It's hard to know, because the way lenses are measured (at least at review sites) they use current generation Canons that would not sample the lens at that resolution in FF. For the central APS-C part you can compare to, say, 7D pixel densities (which are much higher than the current FF lineup). For the region in FF outside APS-C I don't know how you would know (unless the current lenses are already oversampled).

Honestly I see this move to big sensors as an excuse for Canon to update their lenses and bully consumers into update their current equipment if they want to utilise a new FF system with proper AF. /2cents.

I see nothing wrong with that... if you really want/need the higher resolution you're welcome to, but it's not like they're forcing you. The lenses you have wont get worse.

EOS Bodies / Re: Canon 5DmkIII
« on: October 28, 2010, 04:50:38 AM »
Sensor size has very little influence on image quality when comparing sensors of APS H and FF, in fact it is possible to get a better image out of an APS-H because it's not using the weak corners and borders of lenses.

It depends on the lens. If the central 1.3x of FF is more than 1.3x sharper than the outer 1.3x of FF, then yes, otherwise no. Same thing for APS-H, but then with the factor 1.6x.

The fact that they could not distinuguish between one & the other tells a story, but when you consider that one image was taken with a Hasselblad P2 with phase one P45 back, and the other was a Canon G10, that's when you begin to realise that there's an awful lot of BS being talked around the forums.

I think that comparison makes a good point, but at the same time it's a bit misleading. Sure there are situations where you can do just as well with a G10 as a FF or MF camera. The comparison you link to proves that. But there are also situations when the differences between the cameras become evident - in particular low-light or shallow-depth photography, but also in those instances when you really need 39 MP or higher dynamic range.

EOS Bodies / Re: Canon 5DmkIII
« on: October 26, 2010, 08:58:53 PM »
Imagine two people buy an acre of land, one of them builds a skyscraper on it, the other a garden shed, by the logic you're using you would view the two as exactly the same, simply because they each have an acre of land.
You don't know how large the pixel sites are, and as they grow larger they become closer to each other.

Imagine that the two sites have no fences, people from each site are free to pass into each others land, but it's further to go from the shed to the boundary.  Imagine a simple wire fence, everyone can see into the neighbouring plot and some are able to climb the fence into it.  Now imagine a huge concrete wall no one can see it, and no one can pass through.  This is isolation, and it's very important, because you can have small plots where little can pass through and cause noise.

Haha, flake... that was one of the most incomprehensible similes I've ever seen :-) And it had no cars in it. But I agree that larger pixels don't necessarily translate to higher S/N. What mostly matters is the number of photons captured. Whether you capture them on one or four pixels doesn't matter. The exception would be in the very low S/N domain, where the noise becomes read-out dominated. Also, since the well capacity scales closely to the area of a pixel (not volume!), the dynamic range does not change much with pixel size either (the well capacity will be smaller for smaller pixels, but that is exactly made up by there being more of those pixels for an equal area).

EOS Bodies / Re: Canon 5DmkIII
« on: October 26, 2010, 08:46:43 PM »
I currently own a 40D (and I do love it), but my (lucky) girlfriend owns a Nikon D3, and aside from it being a full 35mm sensor, I just think the images that are shot on that seem so much sharper, more in focus, something.

That is most likely due to the lenses she has, aside from the FF advantage. Lenses are usually more important than detectors in producing a sharp image. I also assume you compared images obtained from both cameras by the same photographer, because image quality problems can also be due to what's behind the camera (I'm not saying it is in your case).

EOS Bodies / Re: T2i Replacement?
« on: October 26, 2010, 07:36:32 PM »
But it came out way back in February, and I was wondering if a replacement of it is going to come out anytime soon, because I would rather wait for it.

Waaaay back in February? Not even 10 months old and already worried about its replacement? Ah, kids today...  ;)

It results from spherical aberration - more details HERE and HERE.  Focus shift is generally worse in lenses with intentionally undercorrected spherical aberration, like the 50mm f/1.2L where some sharpness is sacrificed to produce better bokeh.

Thanks, that is a good write-up (and I found some other interesting posts on the toothwalker site). I had no idea manufacturers were deliberately under correcting aberrations to improve the bokeh.

Lenses / Re: Is the EF-S 35mm f/1.8 coming?
« on: October 25, 2010, 07:53:31 AM »
I see your point about f/1.8 v f/1.4, but is 30mm not closer to standard than 35mm?  30x1.6=48, 35x1.6=56.

If you go by the definition that the focal length for a normal lens should equal the diagonal, then the APS-C would have a normal lens at 27.3 mm (and the FF at 43.3 mm; 50 mm was chosen as a "standard" out of manufacturing convenience in the early 20th century)). But yes, 50mm on FF is obviously more similar to 30mm @ APS-C, but anything 25-36mm can be considered normal on the APS-C... the practice is rather arbitrary.

If he was that bothered about IQ why isn't he shooting medium format, or even large format film?

I think he is! Considering he tried to improve the FF IQ by mounting a medium format lens  ;D

Damien Hurst is a UK modern artist producing modern art on a commercial scale at very high prices, a lot of it is very controversial, such as a cow cut in half and preserved in formaldehyde.

Ah, yes, I've heard of that one.

Composition? no need to bother with that when you can crop it when you get back, in fact the only thing a photographer needs to do is to press the shutter at the right time and make sure it's in focus, the back office can do the rest!

Yes, "f/8 and be there". But it depends on the kind of photography you do, and there's far more to composition than just the framing.

Using the pop music analogy, it's like finding that a singer is miming on stage & using auto tune in the studio because they can't really sing, people still buy the albums and go to the live performances, and people believe that their idol is an 'awesome singer'

Well, yeah, although possible, I wouldn't think that happens too often, in either profession...

Focus shift is where the point of focus changes on stepping down the aperture.

Ok thanks, I didn't think of that. It's weird though, since the light obtained by stepping down (in the pupil plane) is a subset of the wide open light. That must mean that the foci for the different pupil radii aren't aligned, blurring the image at wide open aperture.

I was about to get a Nikon D7000, but have heard a lot of complaints about dead pixels in video shooting.

Can't you return it if it has bad pixels? Or try it when you before you commit? I agree that the swivel screen is a great feature on the 60D, but if most of your friends have Nikon, I'd still go for the D7000 (so you can trade lenses with them  :) ). Currently the D7000 also seems to be the better deal, feature wise (compared to 60D).

This guy at least tried a more controlled comparision betw. the 85 lenses.

Thanks, that was better, though I found the following puzzling:

It is a harder lens to use, since it is manual focus only and exhibits focus shift at close focusing distances that needs to be compensated for.

I though that focus shift was the difference between the AF determined focus and the real focus. How can there be a focus shift on a MF lens? He must mean something different, any idea what?

How can I say this?  Well partly because I know a professor involved in optics

Would you care to elaborate? I know an MD, that doesn't make me an authority on heart failures  ;)

BTW have you ever seen any of his work? If not, how can you call him a poor workman.
When someone demonstrably is talking nonsense I think it's quite easy!  After all he's the one who's saying that the equipment is letting his photography down and it's not as good as it could be.

I think it's fair to say that you can talk nonsense and still be an awesome photographer. And technically, your photography can always be improved. So there's no contradiction.

There are plenty of very good photographers around, a lot of making a success comes not from some kind of superior ability, but from luck, contacts, being in the right place, etc. etc.

Yes, but it's not sufficient, you have to have some minimum talent. But I don't think that talent necessarily is as intimately connected to the ability to evaluate the equipment as you seem to believe.

Just like many other professions.  I wonder how many people could say hand on heart that Damien Hurst, or Tracey Emin are the absolute best living artists, and that there is no one in the UK / World as good?

I don't have a clue about who you're talking, but I see your point ("not necessarily the best get famous and credit" etc). My point, however, is that you can be an artist without being able to evaluate the microphone in a satisfactory way. You can even complain how quality of the microphone is limiting your work, and still be an awesome artist!

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