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Messages - epsiloneri

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316
EOS Bodies / Re: Canon 5DmkIII
« on: November 03, 2010, 04:31:58 AM »
I understand your point, but you're talking about the artistic side.

No, I'm not talking about the artistic side, I just gave the bird as an example. I could just as well have said "the ability to image an intensity distribution of a given solid angle that just fits onto the FF sensor".

Of course you can test the sensors only, without an optical system. It's the statement "bigger sensors collect more light" that is misleading. I agree that photosite size is only of second-order importance for a well-sampled image.

317
Well, as I said, I guess it depends on your friends. I assume you wouldn't lend them your car either then, since a lens usually isn't more expensive than a car (or even the service costs to a repair a damaged car).

But I think I start to see your point: it's the loss of control that worries you. Even if you got the lens back in apparent perfect condition, how do you know it had been handled with perfect care?

Regarding a pro pool, I have a feeling amateurs are much more touchy about their gear than pros. A minute scratch on the front lens of no consequence for the IQ would in general not bother a pro while an amateur with a personal attachment to the lens would be devastated. In general, I say, but I'm sure there are plenty of exceptions on both sides.

318
EOS Bodies / Re: 5D Mark III Specs [CR1]
« on: November 02, 2010, 07:13:25 PM »
The specs seem like what I'd expect actually, though the non-100% viewfinder surprises me.  I guess it'll still be larger than the 7D's however.

Yes, I wonder about this as well, in general. Why aren't all view finders 100%? 98% seems so close to 100%, what makes the last 2% so hard? In contrast, I don't find the magnification factor as important. Sure, with a higher magnification you are probably able to discern more detail, but for composition it's a bit tiring on the eye to roll around too much to cover all corners of a magnified frame (for FF, for APS-C it's no issue).

You're right that the 5D viewfinder is much larger than the 7D.


319
but if most of your friends have Nikon, I'd still go for the D7000 (so you can trade lenses with them  :) ).
Ha, ha...worst suggestion ever.  Lenses lost, friends lost.  I wouldn't loan out any of my lenses, except maybe for the film-era EF 24-90mm III which I wouldn't care about losing.

Well... I guess it depends on your friends. I have no problems in trading lenses with my friends. Of course I would fully expect a lost lens to be replaced, that goes without saying, it's part of the deal. I'd do the same. I think lens-sharing is perfect for specialty lenses you don't use/need that often, like fish eye, macro, tip-tilt, super tele.


320
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.

321
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

322
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.


323
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...

324
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.

325
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.

326
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).

327
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).

328
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...  ;)

329
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.

330
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.

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