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Messages - qwerty

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I have a (probably dumb) question. If everytime a new camera comes out and we need a new version of LR to utilize the RAW files, can we convert those files to DNG first and run the DNG file in a previous version of LR?

Is that why the Adobe DNG converter is free?? So you can do that?


Good question. I'm no expert, but what I've taken from my reading is that the DNG converter creates a DNG "wrapper" around the original RAW file, without actually changing the RAW data from the original file. If that's the case, unless one of the manufacturers migrates to a new RAW format (how many years has Canon been on CR2 now?), I don't see how it makes any difference from which model camera the RAW file originates.

I'm personally slow to migrate to new technology, so Adobe has already long since supported any model camera I buy. It would be interesting to hear from someone who has purchased a model before it is officially supported by Adobe, but that uses an existing RAW format, and what their experiences were when attempting to open those files in LR or PS.


A DNG (hopefully!) contains the same information as a RAW file (1), except in a different format.  It is thus more than just a wrapper around the raw data, but the practical difference does not really matter.  I believe that both .dng and most raw files are based on tiff, so there are probably some strong internal similarities.

For more information, see http://www.adobe.com/content/dam/Adobe/en/products/photoshop/pdfs/dng_spec_1.4.0.0.pdf
plus the obligatory wiki page
http://en.wikipedia.org/wiki/Digital_Negative
and (for an older description of .CR2 files)
http://lclevy.free.fr/cr2/

DNG has an option to keep the original raw file embedded in the dng, but that is not required.

You can use the free converter to convert raw files from an unsupported camera to .dng files and edit these in lightroom.

(1) CR2 files actually contain embedded jpegs for previews and whatnot; those probably aren't the same between raw files and dng files.  But the actual raw image information should be the same.

2
Lenses / Re: State of large aperture lenses & digital cameras
« on: December 11, 2013, 06:03:25 PM »
qwerty, all I can say is that if the out of focus light wasn't reaching the sensor, then a f/1.2 image would like the same as a f/2 or higher image.  I can tell you that is not the case at all - the f/1.2 image will have much shallower DOF.  The effective ISO is getting an artificial boost, so we're being "robbed" of image quality in terms of noise, color, and DR (at least at higher ISOs).  At the end of the day, fast lenses are still great for shallow DOF, fast AF, and they will always let in more light, even if the ISOs are getting a boost.


Noone ever said that a larger aperture didn't give you a smaller DOF or allow a shorter exposure time with the same (real) ISO.  The issue is that you don't get all of the benefit you expect based on the change in aperture; if I recall correctly, it's something like half a stop of benefit going from f/2->f/1.4 instead of a full stop.  I suppose the way to experimentally compare DOF would be to compare a digital camera to a film camera.

(Note: I just found http://photo.stackexchange.com/questions/4459/do-dslrs-play-games-with-iso-when-used-with-fast-lenses; I guess you could compare the diameter of a point blurred to see the effect of incidence angle on effective aperture.  However, you can't just take the outer diameter of the disc, because the problem isn't that _none_ of the light gain from the larger aperture gets in, but that not all of it gets in, so you would need to look at the falloff function.  I might actually play around with this later this week.)

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Lenses / Re: State of large aperture lenses & digital cameras
« on: December 11, 2013, 03:44:16 PM »
The way I see it, is that extra light or not, you're still getting the amazing shallow DOF and bokeh with fast lenses

Problem is, it's those same high incidence angle photons that give you the shallow DOF as well.  A sensor that is better at capturing them or a lens that compensates for the sensor's shortcomings would still help you out.


At the risk of re-opening a previously opened can of worms (the kind found in canned apples that KR might use to make a Pi), light falling at extremely oblique angles from a lens with a very wide aperture is detected at progressively reduced efficiency by smaller pixels, but that doesn't make the out of focus light at those wide apertures less out of focus.  When you open up from f/2 to f/1.2, for example, the extra light isn't all hitting the sensor at progressively more oblique angles.  If that we're the case, only the OOF regions of the image would be darker, and the clandestine ISO boost the camera applies would have to be selectively applied only to those regions.


My (admittedly limited) understanding is that (at least in the middle of the frame) the extra rays coming in from increasing the aperture actually do hit the sensor at a more oblique angle.  (For an object at the edge of the frame its a bit more complicated; rays hitting on the same side of the lens are less oblique and the ones hitting the other side are more oblique).

Your "if that were the case..." argument seems to implicitly imply that the in-focus portions of the image _don't_ result from similar oblique rays (i.e. that oblique <-> oof).  However, in or out of focus does not depend on the angle of the incident light on the sensor, but rather rather the rays are focused.

I am not an expert on optics by any means, so feel free to correct me if I am wrong.  In a couple minutes of searching, there is at least one other fool out there on my side on digital diminishing blur.
http://www.luminous-landscape.com/essays/an_open_letter_to_the_major_camera_manufacturers.shtml

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Lenses / Re: State of large aperture lenses & digital cameras
« on: December 11, 2013, 01:32:18 PM »
The way I see it, is that extra light or not, you're still getting the amazing shallow DOF and bokeh with fast lenses
Problem is, it's those same high incidence angle photons that give you the shallow DOF as well.  A sensor that is better at capturing them or a lens that compensates for the sensor's shortcomings would still help you out.


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Lenses / State of large aperture lenses & digital cameras
« on: December 11, 2013, 11:22:11 AM »
Camera makers artificially boost the ISO (i.e. invisibly set the ISO and noise to be higher than what you told it to) when you are using apertures wider than f/2.8 because digital sensors don't capture the rays coming in at oblique angles (i.e. large relative angle with the normal vector) very well.  (This also has implications with respect to the amount of background blur; film will give better blur at large apertures.)  This means that larger apertures have less benefit than you would naively expect on digital cameras.

My question is whether newer lenses and sensors do better in this regard than older ones.  Does anyone have the means to test this?  If you have a "newer" fast lens, you just need to set the aperture, remove the lens (you need the lens attached to stop down the aperture), tape the contacts (to keep the camera from ISO-cheating), take a test shot, and repeat with a set of aperture/time combinations that should give the same exposure. (1)

I am particularly interested in the Sigma 35mm on a 5d iii, 1dx, or 6d (what with the talk of a new Canon 35mm and all)

(DxO measures the lens transmission in T-stops, but they only seem to do it wide open {at least as far as I can see with recent lenses}, so you can not tell the difference between light loss due to poor hemispherical integration at the sensor and other sources, e.g. reflections or manufacturers lying about the aperture.)

(1) One potential problem with this testing methodology is that the advertised aperture is usually different (read: faster) than the actual aperture.  I do not know if the apertures reported when stopped down are accurate in an absolute sense or based on number of stops from wide open.

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EOS Bodies - For Stills / Re: IQ comparison; or how meaningful is DXO
« on: September 06, 2013, 03:47:59 PM »
Just to try to drag the thread back on-topic, here are my favorites in each row:
1d
2a
3d
4b
5c (d had less noise, but seemed oversmoothed)
6d (d had less noise and seemed "sharp enough", but I get the feeling that if there were more detail it would have looked oversmoothed)

I want to thank the OP for making this comparison, and would be curious to see more of the same.  I know a few issues have been pointed out in the thread, and a second pass might be even better.

If I had the time, what I would do is download the raw files of a standard scene from somewhere (I thought dpreview posted them somewhere, but either I am misremembering, bad at searching, or they took them down when they added their scene comparison widget) and convert them yourself using lightroom with the same settings, except scaled so that the image sizes are the same for the different cameras.  You can even keep them as tiffs until final conversion to keep everyone (less un-)happy.

Oh, and how about a less inflammatory title for the next thread? : o )

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EOS Bodies - For Stills / Re: IQ comparison; or how meaningful is DXO
« on: September 06, 2013, 12:14:23 AM »
I do not think there is much disagreement that their sensor tests, methods, and results are accurate and meaningful (at least for some uses).


Yes there is. The biggest debate I've seen in other forums is over their DR scores which do not match the results from other testers (dpreview; IR) and do not seem to match real world experience. IMHO a simple Stouffer transmission step wedge test is far more accurate and reliable then DxO's methodology.

DxO also "interprets" DR based on output/viewing size, which is absurd to me.


Sorry, too long of a day for a fully coherent post, but:

If I am not mistaken, DPreview reports the dynamic range of processed jpegs, not of the raw files themselves.  Basing the measurement on processed files means that the DR reported depends on the processing applied during conversion (which is why they have several different dynamic ranges reported for each camera at each ISO).  (Also, the files they post for "raw" comparisons are obviously not really the raw files; I believe they are ACR conversions to jpeg from the raw files). 

DxO's real business is making raw converters; they analyze the sensor outputs to optimizer their converters (which is why they look at the actual raw data, not processed images).  They would tell you that the DxOmarks are just a side effect of their core business...

With regard to DxO's normalization, I think it would be absurd to compare non-normalized results.  Normalization tells you how things will perform for a fixed print size (which is what most of us care about, as opposed to per-pixel values).

I checked their math a few years ago and they do it right (see http://www.dxomark.com/index.php/Reviews/Detailed-computation-of-DxOMark-Sensor-normalization and check for yourself if you do not believe me).

Comparing non-resolution-normalized results for cameras with different sizes is akin of comparing prints of different sizes.  It would be like comparing a 4x5 print from a 4 MP 1D with 8x10 from a 18 MP 1DX (from the same viewing distance)...


... ... ...
But, all that aside, if you just click the "screen" button when viewing the DxO results, they will happily give you the non-normalized values you want.

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EOS Bodies - For Stills / Re: IQ comparison; or how meaningful is DXO
« on: September 05, 2013, 05:25:38 PM »
DXO measures the sensor characteristics.  Those are hard facts. 

No, they are the results of DxO's testing process and interpretations. There's quite a bit of disagreement as to whether or not DxO's tests are accurate and/or meaningful.

I do not think there is much disagreement that their sensor tests, methods, and results are accurate and meaningful (at least for some uses).  The disagreements are to 1) whether the reported scores (scores, as opposed to test results) are fair, useful, meaningful or what-have-you 2) whether the differences matter for a given user and 3) the fact the DxO only measures sensor performance, not camera performance (and does not claim to do anything different).

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EOS Bodies / Re: 70D and Dxomark....
« on: September 02, 2013, 01:04:45 PM »
I might even go and...(gasp)...take a photo or two, and...(gasp)...enjoy it! :D
I tried that, but the fact that I have only 11 stops of DR just sucked the joy right out of it.  ::)
I usually drive to the coast here which tends to be foggy. Even a Canon can handle that reduced DR. You should try it one day

So, you're saying I shouldn't have tried to take a picture from inside a pitch black tunnel and capture the graffiti sprayed on the black walls with black paint and in the same shot capture the kids' white chalk drawings on the white sidewalk in full sun just outside the tunnel?  Was that where I went wrong?  I bet a D7100 could have done it, though, right?  Sadly, I'm stuck with this PoS, poor dynamic range 1D X. As the actor-turned-Mayor-of-Carmel once said, "A man's got to know his limitations."

A man's limitations should be his limitations, not his equipment's; it's a poor craftsman who has poor tools.  You need a camera that can capture all of the detail in the scene.  One crucial aspect you left out of your scenario is the sun itself -- you absolutely have to have the option of having it in the scene without blowing any highlights. (If you can't see how many sunspots there are, you either have blown highlights, not enough resolution, or too little DOF.)  I think the EV for the face of the sun is in the low 30s, so a 40+ stop sensor is what you should be looking for.   The 7100 won't do that, but I hear Canon will come out with something that beats SoNykon's sensors soon (and for a much lower price than their current lineup).  You should not take any pictures until you get that camera.  Anyone shooting with a current Canon or Nikon camera is just wasting their time.


Seriously though; if we all pitch in, we can get this to be a 100 page thread with no additional content.

(Yeah, I know there is actually useful content in this thread; however the DR stuff adds a lot of noise.)

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EOS Bodies / Re: Why you shouldn't be worried about DR
« on: August 30, 2013, 07:02:10 PM »
you do not know what a selective curve is - do you

You do not know when to stop - do you?

We get it. Nikon is better. How many more times need you tell us?

He won't quit until he gets 14 "stops".  ;D

What halfway serious photographer would be content with only 14 stops??? 

Last time I was shooting for fun,  I needed something like 19-20 stops of DR (graffiti in an abandoned basement at EV 1-2; looking out into daylight at EV 13-14).  To get the shadows indoors and the highlights outdoors on my 5d III, I had to take 5 exposures at 2 stop increments.  (For those of you keeping score at home, DxO reports the DR @ 8MP; the DR at full resolution will be lower by almost a stop.  In theory I could have gotten away with taking exposures in an 8 stop range instead of 10 stops.)  Obviously some scenes can not be captured in multiple exposures like this.

To get this extra 8 stops, all we need are bigger sensors; doubling the edge length of a sensor (and keeping the per-pixel tech the same) will give you one stop of DR (at the original resolution), with a free resolution boost in the midtones.  So, I just need Canon to come out with a sensor of (36*2^8) mm format (about 30 ft), and I will have all the DR I needed for that shot (assuming I was content with a resolution of 20-some MP in the shadows).  On the other hand, an Exmor sensor with its built-in 2 stop DR advantage would only need to be (36*2^6)mm (about 7 1/2 ft) -- small enough to mount on your truck. 

Looking at it another way, all Canon would need to do to match Nikon's 2 stop DR advantage would be to make sensors with their current tech that are about 100x150mm.  (And you would get a huge boost in resolution when you are not limited by read noise.)  Or maybe, in the interest of fairness, we could convince Nikon to replace their FX line with a 4x crop sensor so us Canon fanboys won't feel inferior.


You know, sometimes I can't tell where I am on the serious-sarcastic spectrum... time for the weekend.

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Lenses / Re: Yet another question re ultrawide lenses
« on: August 30, 2013, 03:15:08 PM »
Just wanted to second Random Orbits and Stig.

The SamBowRok 14mm 2.8 is a great lens, especially for the price.  Manually focusing is pretty easy with an UWA lens, and you can buy focus confirmation chips pretty easily off of eBay if you like.  (You can also just focus in live view, since buildings don't move around too fast).

With regard to the sensor size, there is no replacement for displacement.  Mosey on over to TDP and play with their comparison tool.
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=271&Camera=736&Sample=0&FLI=0&API=0&LensComp=100&CameraComp=453&SampleComp=0&FLIComp=0&APIComp=2
Mouse over on the image and see the difference that a FF sensor makes (10mm at f/3.5 is roughly equivalent to 17mm at f/5.6, meaning they have the same AOV, DOF, and photon shot noise for a given illumination and exposure time). 

If you look at the result of having both lenses mounted on the same camera, you can see that the lenses have a similar resolution (i.e. lp/mm), and perhaps even giving the 10-22 a slight edge, but going to full frame  gives a higher resolution on the final image
http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=271&Camera=736&Sample=0&FLI=3&API=0&LensComp=100&CameraComp=736&SampleComp=0&FLIComp=0&APIComp=0

That said, the best UWA lens regardless of format is probably going to be some 8x10 format lens.  I am not sure how wide they make them (you might have a very limited or no selection wider than 17mm equivalent), but a mediocre 8x10 lens will blow away an awesome full frame lens in terms of image resolution.  However, if you mounted this hypothetical large format lens on a FF or APS-C body, you would be underwhelmed by the result, as you would loose the advantage of the larger format.

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EOS Bodies / Re: 70D and Dxomark....
« on: August 28, 2013, 05:22:42 PM »
70D and Dxomark... As far as I have learned here on this forum, their assessment is not the last verdict...;-)

http://www.dpreview.com/forums/post/52066617


You are in violation of one of the 10 commandments of CR (and I probably am in violation of my own commandment for responding...)

Here is at least a link to their actual test results (instead of the not-very-meaningful numeric scores)
http://www.dxomark.com/index.php/Cameras/Compare-Camera-Sensors/Compare-cameras-side-by-side/%28appareil1%29/895|0/%28brand%29/Canon/%28appareil2%29/663|0/%28brand2%29/Canon

(Click on "measurements" then, e.g. "SNR 18%" or "tonal range" to see the results; you can of course add whatever other cameras you want to compare too.)


Looks like a small (not really noticeable) improvement over the 60d.  Nothing groundbreaking as far as improvements in the image quality, but the 70d is all about the improved AF, which is outside the realm of what DxO tests.  I don't see the big deal, or anything to make a fuss about.

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Third Party Manufacturers / Re: Big Sigma Primes [CR2]
« on: August 26, 2013, 12:26:38 AM »

Why Sport? I believe Art signifies 2.8 or larger aperture. It would be a Sport if it was a zoom with a variable aperture.


What??? What kind of a crazy name scheme is that? Sports are where constant aperture is more of a big deal ANYWHERE else.


Quick, someone tell Sigma that they listed their 120-300mm f/2.8 lens improperly on their website.
http://www.sigmaphoto.com/product/120-300mm-f28-dg-os-hsm-s
Oh, and on their press release when they announced their Sports line.
http://www.sigmaphoto.com/article/sigma-corporation-announces-reorganization-of-lens-lineup-new-products-and-quality-control

(Their existing 300 f/2.8, etc. are also listed as sports lenses, though those predate their A/S/C designations)
http://www.sigmaphoto.com/product/120-300mm-f28-dg-os-hsm-s

My guess is that the 35 f/1.4 (which is an art lens) got a lot of good press, so they (the rumor submitter) are piggybacking (likely inadvertently) on that fame.

Anyways, enough semantics.  I am in the market for a 300 or 400 f/2.8, but good quality (Canon Mark 1 with IS) used versions are selling for $3k and up on eBay, which is a bit more than its worth to me.  (The existing Sigma 300mm f/2.8 without OS/IS is a bit over 3k new.)  I don't imagine the new and improved Sigmas will be any cheaper than that, so I am probably out as far as the new market it concerned.  But, I am sure there will be plenty of people on this thread excited about the possibility of Sigma announcing a bargain.  Still exciting though - I like to see competition.

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EOS Bodies - For Video / Re: Canon 5dIII Raw issue
« on: August 25, 2013, 08:35:56 PM »
Magic Lantern is a 3rd party software hack. I'm nearly certain that negates your warranty.


I cant help the OP, but according to a story reported on this noble site, as of a few months ago, Canon is playing nice with ML for warranty repairs.
http://www.canonrumors.com/forum/index.php?topic=15049.0

Now, if Canon says the problem is ML's fault and not their fault (and does not affect, and can not be used to effect (1), approved use of the camera), they might not be too helpful in finding a fix.  But if the problem bugs you, its probably worth a shot.


(1) always use effect as a verb and affect as a noun when you can (almost) get away with it.
http://xkcd.com/326/

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Site Information / Re: The 10 Commandments of CR
« on: August 25, 2013, 07:29:58 PM »
Thou shalt not believe in false scores of DxoMark


Thou shalt remember that only lens scores from DxOMark and any overall summary scores are false and thou shalt believe in their individual sensor chart scores, for they are true and good.

+1 

With related commandments/corollaries:
1) You shall ignore any comment that says that you should disregard DxO because their single number scores are meaningless (whoa, meta! -- read as Ted Logan) and you shall not make such comments.

2) You shall ignore any comment that says camera A is better than camera B because it has a higher DxO (sub-) score, and you shall not make such comments.  Same goes for "lens A is better than B because it has a higher resolution score", etc.

3) You shall remember that the DxO charts are just one of many measurements of camera quality; the camera system is much more than the sensor (or lens), and DxO isn't even the only group doing measurements on the sensor (or lens).

(Though I don't know anyone else who gives low-level or resolution-corrected results as well or for as many sensors as DxO.)

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