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Author Topic: Canon 50D @ 15MP  (Read 115223 times)

Tony Beach

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Canon 50D @ 15MP
« Reply #140 on: September 01, 2008, 04:43:37 pm »

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No. You haven't interpreted correctly what I wrote. I'll try again. In circumstances where at F11 the time on that tower clock (the tower clock as identified in the F8 shot) is just legible in a 50D shot, it probably wouldn't be legible in a 40D shot at the same aperture of F11.[a href=\"index.php?act=findpost&pid=218633\"][{POST_SNAPBACK}][/a]

You wrongly assume that the 50D will not lose acuity at f/11 and will still show the hands on the clock.  If the hands can no longer be seen at f/11 on the 50D, then you have gained nothing over the 40D.

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Of course I know that all good 35mm lenses will be marginally sharper at F8 than at F11. Why on earth would you think I wasn't aware of that?


Regardless of lens, the denser photosites will become the limiting factor even with the best lens.  Is the Airy disk eliminated with a higher quality lens?  Canon shot this landscape scene at f/8 and I believe that wasn't a random choice that they made.  Probably with the lens they used f/5.6 would have had softer corners, and I bet they saw that the f/8 shot was sharper than the f/11 shot (and maybe even the f/9 shot).  Does this mean that the 40D is just as good at f/11 as the 50D?  Hard to say:  AA filters, microlenses, and the lenses used will all play a part in the final outcome; but I still think at f/11 diffraction (as recorded by the photosites) will limit the files to about equal.

I have two excellent landscape lenses:  the Nikkor 14-24/2.8 and the Nikkor 17-35/2.8 -- that's because I bought the latter when money was tighter and it has been banged around (so it only cost me about $500), and now my son uses it on his D200.  I had noticed using the 17-35 that it was always a little soft in the corners at infinity using the hyperfocal distance, but sharp focused at infinity.  The 14-24 on the other hand is actually sharper at infinity using hyperfocal distance than it is focused at infinity, but only at around f/11.  Here's the rub, when I set the lens to a wider aperture and use the hyperfocal distance then my edges (but not the center) at infinity start softening up.  So if I were offered a Nikon DX DSLR that had 15 MP I would gain nothing whatsoever over my D300 because I need to shoot at f/11 to get the most out of my lens and the edges of my landscape photographs would be less sharp at f/8.

I have some excellent lenses, but I will not upgrade to a 24 MP FX DSLR until I have spent over $5000 on 3 more lenses that I consider essential for attaining optimum image quality (24mm and 45mm PCE, and the Nikkor 24-70/2.8).   Also, I will be upgrading my computer because as it is now my system bogs down when I start assembling and editing 20+ MP images, and that's probably another $4000.  I think chasing megapixels without giving careful consideration to what you will do with them is foolhardy -- YMMV.
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Ray

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Canon 50D @ 15MP
« Reply #141 on: September 01, 2008, 08:42:25 pm »

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You wrongly assume that the 50D will not lose acuity at f/11 and will still show the hands on the clock.  If the hands can no longer be seen at f/11 on the 50D, then you have gained nothing over the 40D.
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Tony,
It's not a wrong assumption that the 50D will not lose acuity at F11 or F22 or any aperture you wish to nominate. The acuity of the 50D sensor is fixed. Only the lens will lose acuity as it is stopped down beyond F8.

It's been mentioned several times in this thread that there is some evidence that the higher-pixel-density sensor can continue to provided marginally (perhaps very marginally) greater detail all the way to F32, despite the fact that the theoretical calculation of the size of the Airy disc at such apertures suggests there is nothing to be gained.

My own experience suggests that the contrast of the target will also affect any test results significantly. This is another source of confusion which (for example) prompts many questions about the effectiveness of 1.4x and 2x extenders with a particular lens.

Such questions can never be answered definitively, because it always depends... depends on the contrast and detail of the target as well as the quality of the lens.

After acquiring my Canon 100-400 zoom and 1.4x converter, I took many test shots of distant subjects, with and without converter at 400mm. Even at 200% magnification on the monitor, often I could not see any improvement in detail or sharpness.

However, when shooting closer subjects of high detatail and contrast in bright sunlight, there was always a noticeable improvement using the 1.4x extender.

I imagine the same principle applies when using small apertures with high-pixel-density cameras. There is no brick wall, just a gradual loss of contrast as one stops down. At some point, with a low contrast subject, one will be unable to perceive any improvement in detail or sharpness from the higher-pixel-density sensor. Change the subject (or target) to one of very high contrast, then detail that previously was indiscernible at the same F stop (say F11 or F16) becomes discernible.

I can to some extent sympathaise with your point of view. I was also of the opinion that there's nothing to be gained at diffraction limited apertures with the higher-pixel-count cameras. This is of some concern to me since I have my eye on one of the next 24mp FF cameras which have approximately the same pixel density as my 40D. I was curious if any purpose would be served at F16 and F22, apertures which I can use with my 5D but would hesitate to use with the 40D.

Some of my test results can be found at [a href=\"http://luminous-landscape.com/forum/index.php?showtopic=26420]http://luminous-landscape.com/forum/index....showtopic=26420[/url] , a thread started by dwdallam who was apparently concerned about the performance of his 1Ds3 at such apertures.
« Last Edit: September 01, 2008, 09:34:07 pm by Ray »
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meyerweb

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Canon 50D @ 15MP
« Reply #142 on: September 01, 2008, 11:09:14 pm »

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It is my contention that by the time you reach f/11, there will be no difference between a 40D file and a 50D file. 
[a href=\"index.php?act=findpost&pid=217510\"][{POST_SNAPBACK}][/a]

Assuming you're correct, that still leaves an awful lot of subjects shot at f8 or wider where, I think you would agree, the 50D would show an advantage. I would hazard a guess that well over half of my photos are shot at f8 or greater.

Time will tell how the camera stands up to Canon's claims, but I believe it appears to be a significant advance over the prior xxD bodies. Would applying the new microlens technology to a 12 mp sensor have been a better alternative?  Perhaps for some, but maybe not for all.

As long as image quality at f11 and smaller is not WORSE than the 40D, I'll take the improved resolution at larger apertures, along with improved live view, lens microfocus adjust, the higher res LCD, etc.  In fact, if this camera lives up to the hype, it's the first xxD body that offers enough of an advance to make me replace my 20D. I'll give it to my wife, keep the 1DII for situations where AF performance is the highest priority, and use the 50D for everything else.   IF the camera lives up to Canon's hype.
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Ray

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Canon 50D @ 15MP
« Reply #143 on: September 02, 2008, 09:10:04 am »

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Assuming you're correct, that still leaves an awful lot of subjects shot at f8 or wider where, I think you would agree, the 50D would show an advantage. [a href=\"index.php?act=findpost&pid=218810\"][{POST_SNAPBACK}][/a]

Absolutely! We should bear in mind that F8 on the Canon cropped format is equivalent to F13 on full frame 35mm, regarding DoF. Even if the lens used is sharpest at F5.6, that's still equivalent to a 35mm F9.
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Slough

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Canon 50D @ 15MP
« Reply #144 on: September 02, 2008, 03:37:35 pm »

The MP seems pointless and counterproductive to me. Very very few lenses are good enough to use 15MP. And I'm not talking just resolution on axis, but corner resolution, and CA. And even then, they can only use that 15MP when at about F8. So, how many shots do you take with the finest lens, on a solid tripod, with perfect technique, at low ISO (so as not to lose IQ) and F8? Very few is my guess. And yet you need to store 15MP files. Oh, and how big do you need to print to see the advantage over 12MP?

Nice camera though in terms of the other specs i.e. build, FPS, AF etc. Looks like Canon have finally caught up with Nikon by selling an APS camera with a high price.  I always though the 40D was more than enough though.
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Panopeeper

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Canon 50D @ 15MP
« Reply #145 on: September 02, 2008, 04:06:38 pm »

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So, how many shots do you take with the finest lens, on a solid tripod, with perfect technique, at low ISO (so as not to lose IQ) and F8? Very few is my guess
Most of my shots. The exception is, when I can shoot it hand-held, but ISO 200, f/8 or f/11.

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And yet you need to store 15MP files
I don't see any problem there.

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I always though the 40D was more than enough though.
More than enough of what? Pixels? Already the 20D was enough for me. Dynamic range? The 40D is far from what I would like to have.
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Gabor

Slough

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Canon 50D @ 15MP
« Reply #146 on: September 02, 2008, 05:06:03 pm »

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Most of my shots. The exception is, when I can shoot it hand-held, but ISO 200, f/8 or f/11.
I don't see any problem there.
More than enough of what? Pixels? Already the 20D was enough for me. Dynamic range? The 40D is far from what I would like to have.
[a href=\"index.php?act=findpost&pid=219007\"][{POST_SNAPBACK}][/a]

I think you are the exception in terms of technique. Okay, so you seem to agree that the extra MP is not of interest to you. Dynamic range? Yes, we can all hope! Though for me the extra DR over slide film, and the ease of getting white balance without CC filters makes digital a winner.
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Panopeeper

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Canon 50D @ 15MP
« Reply #147 on: September 02, 2008, 05:27:57 pm »

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I think you are the exception in terms of technique
Are you never shooting landscapes?

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Though for me the extra DR over slide film, and the ease of getting white balance without CC filters makes digital a winner
Well, Morse was a winner over letters carried by couriers, so why are we having phone, fax, email, mobile phone?
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Gabor

sojournerphoto

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Canon 50D @ 15MP
« Reply #148 on: September 02, 2008, 05:30:31 pm »

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I think you are the exception in terms of technique. Okay, so you seem to agree that the extra MP is not of interest to you. Dynamic range? Yes, we can all hope! Though for me the extra DR over slide film, and the ease of getting white balance without CC filters makes digital a winner.
[a href=\"index.php?act=findpost&pid=219019\"][{POST_SNAPBACK}][/a]


At the risk of intruding on the thread, whilst Panopeepers technique is unusual it is also the reason he doesn't need more pixels. Since I suspect that he specialises in panoramas he can get as many pixels as he needs by chooisng the most appropriate lens.

On the 50D, I looked at the landscape sample as was a bit disappointed actualy. That may just be the subject, but I'de expected better given the hype.

Mike - a happy canon user!
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fike

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Canon 50D @ 15MP
« Reply #149 on: September 02, 2008, 07:29:51 pm »

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At the risk of intruding on the thread, whilst Panopeepers technique is unusual it is also the reason he doesn't need more pixels. Since I suspect that he specialises in panoramas he can get as many pixels as he needs by chooisng the most appropriate lens.

On the 50D, I looked at the landscape sample as was a bit disappointed actualy. That may just be the subject, but I'de expected better given the hype.

Mike - a happy canon user!
[a href=\"index.php?act=findpost&pid=219025\"][{POST_SNAPBACK}][/a]

I also shoot a lot of panos....actually most of my serious photo work is panoramic.  Right now, with an 8MP camera I can make a single row pano up to about 14" tall by any dimension wide.  My largest work was 7 rows of 9 images.  

To get up to 17" or even 24" I need to shoot mosaics of multiple rows.  This requires a more complex tripod head (spherical versus cylindrical) which adds more weight to my gear.  I am hoping that the 50D resolution is enough to allow me to get something like a 20" tall panoramic print with only a single row of images.  At 240 DPI, if the 50D images benefit from all of its available resolution, I could print up to 19.8" tall.  If I am limited to F/8 or F/11, that would be acceptable to me.  


Pano people are obsessed with large detailed images...I guess that is why he is so concerned with resolution that goes beyond useful resolving power of the sensor/lens combo.
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Panopeeper

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Canon 50D @ 15MP
« Reply #150 on: September 02, 2008, 09:05:46 pm »

Pixel count is often less a concern in panomaking than in "normal" landscaping, although if I can I avoid shooting two rows instead of a single row only for the sake of a few hundred extra pixels.

Dynamic range is a bigger issue in panomaking. The dynamic range of a wide (or tall, for that matter)  scenery may exceed by a lot that of a single frame. Although I often shoot the frames with variable exposure, this involves quite much preparatory work for the stitching; it is much simpler to shoot all frames with the same exposure - but then one needs sometimes three stops extra DR.

However, shooting from tripod with low ISO, aperture as small as diffraction allows and still ideal exposure is IMO nothing special in landscape shooting. For me the biggest issue (beside the DR) is in most cases the compromise between DoF and diffraction.
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Gabor

Ray

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Canon 50D @ 15MP
« Reply #151 on: September 02, 2008, 09:51:24 pm »

Perhaps someone could provide some test shots comparing image sharpness of the same scene at various ISOs. I get a sense there's a slight drop in resolution at ISO 800 and 1600 with the 5D, but do not hesitate to use ISO 400 when needed for the required shutter speed.

The 'sunny 16' rule indicates that correct exposure for an open landscape on a sunny day is 1/ISO. At ISO 100 that's 1/100th of a second at F16 and 1/400th at F8. I see no problem there.

Choosing a sufficiently fast shutter speed for a sharp image is a basic photographic technique. Unfortunately, circumstances are such that it's sometimes not possible, due to poor lighting. Using a tripod doesn't necessarily help if the subject is moving.

One feature which I'd find very useful, which I believe only certain Nikon cameras offer, is automatic ISO in relation to a chosen shutter speed and aperture. I can't understand why Canon do not offer this feature now that DSLRs produce such excellent image quality at high ISO. Even with an IS lens, I'd rather use 1/100th at ISO 800 than 1/13th at ISO 100, hand-held. With a telephoto lens, say 400mm with image stabilisation, I'd rather use 1/400th at ISO 1600 than 1/200th at ISO 800.
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Panopeeper

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Canon 50D @ 15MP
« Reply #152 on: September 02, 2008, 11:38:36 pm »

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The 'sunny 16' rule indicates that correct exposure for an open landscape on a sunny day is 1/ISO
What is the role of in-camera RGB histogram in the "sunny 16" rule?

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Even with an IS lens, I'd rather use 1/100th at ISO 800 than 1/13th at ISO 100, hand-held. With a telephoto lens, say 400mm with image stabilisation, I'd rather use 1/400th at ISO 1600 than 1/200th at ISO 800.
You mentioned a "sunny day" just above. What about the dynamic range?
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Gabor

dwdallam

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Canon 50D @ 15MP
« Reply #153 on: September 03, 2008, 04:16:16 am »

I have a question for you all:

5D or 50D if you had to choose one or the other?

And just for giggles---Digic 4 processor and the Digic 3 has been out less than a year. I feel ripped off with my 1DS3. Can you image the 1DS3 with the Digic 4? I can, but I just bought the 1DS3. I knew I should have waited a year to upgrade.
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Ray

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Canon 50D @ 15MP
« Reply #154 on: September 03, 2008, 10:39:20 am »

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What is the role of in-camera RGB histogram in the "sunny 16" rule?

To make sure those fluffy white clouds are not clipped.

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You mentioned a "sunny day" just above. What about the dynamic range?

I don't believe even an MFDB will capture dense, undergrowth shadows cleanly with unclipped, fluffy white clouds in the same scene.

I would not expect the 50D, considering the image as a whole at a specific size on monitor or print, to have less dynamic range than the 40D, although the individual pixels might have very slightly less.
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Ray

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Canon 50D @ 15MP
« Reply #155 on: September 03, 2008, 10:43:24 am »

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And just for giggles---Digic 4 processor and the Digic 3 has been out less than a year. I feel ripped off with my 1DS3. Can you image the 1DS3 with the Digic 4? I can, but I just bought the 1DS3. I knew I should have waited a year to upgrade.
[a href=\"index.php?act=findpost&pid=219117\"][{POST_SNAPBACK}][/a]


Isn't the Digic processor only relevant for jpeg shooters?
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DarkPenguin

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Canon 50D @ 15MP
« Reply #156 on: September 03, 2008, 10:50:23 am »

I believe it is what peels everything off the sensor.  So if it is slow you're RAW frame rates will suffer.

I should think that it would also matter for live view.
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Panopeeper

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Canon 50D @ 15MP
« Reply #157 on: September 03, 2008, 11:08:39 am »

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To make sure those fluffy white clouds are not clipped
LOL, that's what I meant. I don't need Noah's rule when I have a built-in metering and histogram.

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I don't believe even an MFDB will capture dense, undergrowth shadows cleanly with unclipped, fluffy white clouds in the same scene
Such general statements are not of much help. Anyway, irrespectively of the total dynamic range of the scenery, two stops more or less make a huge difference for me (that is the difference between ISO 200 and 1600 of the 40D's DR).
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Gabor

Panopeeper

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Canon 50D @ 15MP
« Reply #158 on: September 03, 2008, 11:09:41 am »

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I have a question for you all:

5D or 50D if you had to choose one or the other?
Is this not too early? Based on what would one make a decision?
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Gabor

fike

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Canon 50D @ 15MP
« Reply #159 on: September 03, 2008, 11:53:42 am »

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Isn't the Digic processor only relevant for jpeg shooters?
[a href=\"index.php?act=findpost&pid=219170\"][{POST_SNAPBACK}][/a]

While I know that RAW is considered...well...the raw data, I seriously doubt that the data is taken without any processing at all....just encapsulating the data into a file format, applying metadata and saving the file to compact flash would be some minimal processing task for the DIGIC...that doesn't include the exposure curve and white balance that is applied to the RAW file so that it doesn't look like cr@p when we view it.  

It wouldn't be surprising if some very conservative, baseline sharpening and noise reduction was happening too.
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