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Messages - sarangiman

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sooooo you guys have actually got IQ180 phaseones and D800s that you are personally testing against?

Nope, and therefore I'm choosing to reserve judgement.

I think you may have missed the entire point of my post :)

honestly, I just want full viewfinder spread on FF cameras. canon and nikon's points are all bunched up together. the 5DmkIII in some modes you can't even see what da hell you're shooting because it is like a fly infestation landed on your lens.

+1. Keep preaching sense, psolberg. :)

Quote from: wickidwombat on June 21, 2012, 07:27:50 PM
It still hillariously amusing seeing the D800 squad above the IQ180 kind of sums up the whole DxOhohohoh
credibility right there 

psolberg wrote:
it's ok. denial eventually goes away.

+1 psolberg.

What perplexes me is how confidently some people make statements without doing controlled tests themselves.

But what particularly makes your statement 'denial eventually goes away' appropriate is the whole hoopla surrounding DXO's D800 DR rating & the initial backlash against DXO all over these threads (and other sites) because of those numbers... and the subsequent (final) acceptance of those DR numbers after numerous examples all over the internet of the stops upon stops of increased shadow performance on the D800 vs. the 5D series.

I admit I myself was dubious of DXO's numbers initially... until I did wedge & real-world tests that completely agreed with DXO's numbers. And I was glad I didn't initially respond to those numbers with outspoken incredulity.

Controlled testing & peer review was established for a reason :)

It still hillariously amusing seeing the D800 squad above the IQ180 kind of sums up the whole DxOhohohoh
credibility right there 

I wouldn't laugh before I did the test myself :)

11.89EV pixel-level DR for the IQ180 is not so great, compared to 13.23EV pixel-level DR for the D800. So I'm assuming the IQ180 has considerably higher low ISO read noise... i.e. what plagues Canons. Not sure if the print DR numbers are fair b/c I'm not certain of the validity of their normalization process. Downsizing ~80MP to 36MP would of course lower the noise levels.

I'm sure that the IQ180 has incredible image quality; I'd just be cautious about mocking the actual measurement numbers DXO provide since my own dynamic range wedge tests with the 5D, 5D Mark II, 5D Mark III, & D7000 match DXO's numbers really well... which also match my real-world tests... which also pretty much match what people all over the interwebs are posting these days showing the incredible DR advantage of the D800 (heck even the D7000) over the 5D series.

I don't usually pay any attention to the overall score; I'm only interested in the specific measurements which allow you me to judge a sensor based on my needs.

1D4 9pts(outer) are 3 points in each of 3 rows

I see. My point is that the 5DIII has a cross-type AF point above the upper-most, center, selectable AF point in 9pt mode (and one below the lower-most, center, selectable AF point). Why not use these in the 9pt mode instead of ones closer to the center? You'd get more AF spread... and like I said, photographers are typically talking about more AF point spread, not less.

Enabling those (to create a diamond like spread of selectable AF points) gets you one step closer to an area of the frame that has no AF points at all. I don't really understand decisions such as these. Maybe I'm missing something.

Either way, customizability would solve issues like this in one gigantic sweep.

Customization would be huge, in general.

I personally use the 'all cross-type' option; however, having an option for 9 or 11 or whatever number would be great.

And while we're on the subject, if you look at the mapping of the 9 points --do we even know if those are all cross-type?

Also, for the 9 points, why don't they enable the top-most/bottom-most center sensors (which are cross-type)? Why have that rectangle shape when you could have more of a diamond spread (more AF spread... which is what more photographers, in my understanding, who custom select points typically want anyway)?

At any rate, full customization would just allow photographers to use what they need, which would offer an incredible advantage in terms of speed in fast-paced shooting scenarios.

Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 19, 2012, 04:03:45 PM »
I have found that the 17-40 is best at f/8- f/11. After that the image gets softer, presumably defraction

I absolutely agree with you there. Especially with wide angle lenses, as I understand it, diffraction often sets in earlier b/c the actual opening of the aperture is quite small. E.g. 17mm at f/8 has an opening of diameter 2.125mm whereas an 85mm lens at f/8 has an opening of 10.625mm.

The reason I shot at f/18 was to deal w/ the softness on the left side... it literally kept sharpening up at smaller & smaller apertures even though the center & right started losing sharpness due to diffraction. But I thought: 'better even sharpness across the field, albeit lower, than significantly lower sharpness on one side'. Personal preference, really.

Luckily, I no longer have to worry about such things with my Nikon 14-24! But would really appreciate a Canon alternative similar in image quality...

Posting on this site further softens a jpeg

Yup, resizing algorithms vary, & output sharpening decision of course affect perceived sharpness. I chose to actually not use maximal output sharpening in this particular image b/c of the sharpening halos it created around the buildings.


Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 19, 2012, 02:59:04 AM »
Laughable, the lighting of the two scenes was completely different.  This has become a bad joke and at this point a headache and waste of time.  Adios.
Yup, as I mentioned ages ago: different lighting due to sun sinking lower causing flare, & yet utterly irrelevant to the conclusions of this comparison, as I've already proven.

'Laughable' is more your denial of a study that shows exactly what most other studies have already shown... without doing your own tests. For example, the one psolberg linked to below...

All canon wide zooms and 14mm prime fail to touch the 5 year old 14-24. But that lens won't show up In 2012. I got tired of waiting...

Yup, thank you psolberg!

Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 18, 2012, 11:00:28 PM »
I would say in your new shot that the roads and buildings are approaching sharp, but not sharp, the sky 'is' close enough to sharp for a sky, and the trees and greenery are downright blurry.  I would not call this image sharp, even casually.
I think what you're talking about is 'acutance', or local contrast... yes of course the buildings in this image will have higher acutance than the trees; the local contrast in the trees to begin with in this scene were very low. What is your point? That has absolutely no bearing on our conversation of lens MTF as a function of center vs. extreme.

They aren't even close to a definition of something I would call tack sharp, and 100% crops from 35mm DSLR's rarely are.
You're right, we've had a total breakdown of communication. B/c when I said 'tack sharp', I thought I made it pretty clear that I meant 'about as sharp as you're going to get w/ any lens on this sensor'. Since this entire discussion was about comparing center vs. extreme sharpness on a 5D-ish camera, what would be the point of defining 'tack sharp' in any other way?

You will see you did not match exposure in the images, and hence, measuring sharpness between the two of them at that point becomes rather a fruitless effort as the contrast will never be the same and hence the impression of sharpness will vary.
Actually, the exposures are exactly the same, barring T-stop differences between the lenses. 1/320s | f/2.8 @ISO 100 is equivalent to 1/40s | f/11 @ISO 200.

The flare decreases contrast in the Canon image, yes, & I mentioned this a while back. While I agree that contrast of course affects perceived acutance, I respectfully disagree that the decrease in contrast due to flare on the Canon shots prohibits one from seeing the clearly higher sharpness of the Nikon lens at the extremes.

Because if the decrease in contrast due to lens flare is confusing you about which of the following images is sharper:

Full-size image: http://cl.ly/HQaY/Nikon14-24_vs_Canon16-35_f2.8_Left.jpg

Or which of these images is sharper (remember: 100% crop taken from same portion of frame, so as to not give one shot an unfair advantage):

Full-size image: http://cl.ly/HTEK/Nikon14-24_vs_Canon16-35_Corner.jpg

... then you may have to get your eyes checked :)

Actually, here let me try to prove to you that the decreased contrast does not significantly affect your ability to judge which lens is sharper. I've done -100 contrast to the Nikon image. If you quantify the ratio of the brighter vs. darker siding on one of these buildings, the Nikon f/2.8 image (left) now has less contrast than the Canon f/11 image (right). Do you still have any trouble discerning which is sharper:

Full-size image: http://cl.ly/HTY9/Nikon14-24_-100Contrast_vs_Canon16-35_Corner.jpg

Seriously, I think I can rest my case now. If I were writing this formally as an article on a review site, yes, I would go out & redo the test on a cloudy day (would've done so already if I hadn't gotten rid of the 16-35) when there is absolutely no change in lighting between shots. But you can draw some pretty darn good conclusions from what I've posted here (barring copy variability, of course).

Unusable? Hardly. Especially in light of the -100 contrast (to the Nikon image) 'experiment' above.

Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 18, 2012, 08:17:37 PM »
No, that was a merge of 4 exposures all done using a combination of luminosity/hand-drawn masks. Thanks for the compliments.

Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 18, 2012, 03:43:30 PM »
Great comparison

I wonder how visible this would be on a 30" print? Would the output from the Canon look noticably worse than the Nikon or is this going to more a factor of the body?
Thanks Brian.

Here's an image I shot at f/18 on my 5D w/ a 17-40 a couple years ago:

Larger image here: http://f.cl.ly/items/1I120q0h1n1A1o432J3b/Seattle-RizalBridgeSunset.jpg

Looks plenty sharp at this size, of course, edge to edge. But in a 21"x34" print, the left side is clearly softer than the right. And this was f/18. Did my client that bought the image notice? Probably not :) But then again, we are our own harshest critic, no?

That was when I started my hunt for a better wide angle zoom... beginning w/ trying to get that lens fixed by Canon, buying another copy, buying a 16-35, etc. etc.

Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 18, 2012, 03:38:45 PM »
-Both of the pictures in Saringman's tests that he kindly posted are of an un-usable quality at a 100% viewing, either on a monitor, or on a high end print, --if not viewing close up for fine detail either full images could work but it's not a nice picture so it's a moot point.  Otherwise the 100% crop views on all of the above are unflattering at best and I would say downright unusable.

Respectfully, I really have no idea what you're talking about, & wonder if perhaps you're not used to viewing 22MP images at 1:1. As for it not being a 'nice picture', this was not a landscape shot, it was a test of a field-of-view that contained lots of buildings approximately equidistant from the camera for easy comparisons of sharpness.

The center 100% crops are tack sharp from both lenses for a default ACR setting of 25; you can make it much sharper if you'd like to. I don't think anyone here would disagree with me on this save for you. Are you following the links & viewing at 100%? Are you looking at the buildings/railings to judge sharpness? Don't look at trees blowing in the wind & cars moving... look at the static subjects, which are, again, tack sharp in the center, ruling out motion blur or whatever else you are invoking to attempt to invalidate these tests.

The side 100% crops are what they are, which was the entire point of this comparison.

And if you look at the numbers & graphs I posted earlier (e.g. 26% resolution at the extremes compared to the center at f/2.8 for the Canon, w/ the best the 16-35 can do at the extremes, i.e. f/8, still only 82% the resolution of the worst the Nikon does at its extremes at f/2.8 ), the pictorial examples I've provided should not surprise you at all, unless you also have a problem with photozone.de (who, by the way, do stellar tests).

If you're surprised by these results & would like to contribute to this discussion, I'd encourage you to also try shooting your own flat field tests, maybe even w/ a rental Nikon 14-24 to compare side-by-side. Try to walk in to the test unbiased, hard as that may be. If anything, I was initially biased toward Canon, b/c who'd want to go through all the extra trouble & cost to shoot w/ the Nikon lens on a Canon body, losing AF & aperture control?

As I said earlier, your examples do not provide any indication of how your 16-35 performs on a flat-field, though it's entirely plausible that it performs better than mine did (there are always tolerances in QC & manufacturing). Even if so, I doubt it would be by a wide margin, given the clear lack of decentering issues on my copy, my experience with multiple other copies of the 17-40, & photozone's numbers. Furthermore, your f/2.8 shot clearly shows incredible softness on a good portion of the left side (landscape orientation), even at web resolution. Again, no surprise there.

Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 18, 2012, 01:04:56 AM »
While it's always appreciated to see example shots, I think we should be able to agree that one person's images don't make a definitive argument for or against a lens.
Oh, absolutely. Controlled tests are only meaningful when done in duplicate, triplicate, etc. Multiple copies of lenses, for example. I've only presented data from one 16-35 here, for example, though I did present some aggregate data from 4 copies of the Nikon 14-24... showing you the best/worst performance out of a batch of 4 lenses.

But then, do you know my credentials? Do you trust my testing methodology? Etc., & so on & so forth. Which is why I tried to control as many variables as possible, & provide my testing conditions & RAW files if you'd like to see for yourself.

That being said, allow me to show you a quick visualization of photozone.de's MTF numbers I did of the Nikon 14-24 vs. the Canon 16-35.

As you can clearly see, Nikon extreme f/2.8 performance matches Canon's center f/11 performance (the left endpoint of the blue-dashed line matches the right endpoint of the red-solid line).

Wow, seems strangely reminiscent of the pictorial examples I showed!

Meanwhile, by f/5.6, the Nikon is as sharp at the extremes as the Canon lens ever is, anywhere.

Wow, again, seems strangely reminiscent of the pictorial examples I showed!

Now, let's take a look at extreme vs. center performance for both lenses. I'll plot extreme/center performance ratios, but this time with resolution (2-dimensional, meaning LPPH numbers have been squared) as a function of aperture), 1 being equivalent extreme vs. center performance:

Both lenses are so sharp at the center that the extreme performance only begins approximating center performance after center performance is depleted due to diffraction effects. But the Nikon lens almost approaches center/extreme equivalence by f/11, while the Canon still only shows ~79% extreme vs. center performance by f/11. At f/2.8, extreme resolution is at a staggeringly low 26% of center performance for Canon, while the Nikon extreme/center performance is at 62%.

Meanwhile, the Canon extremes never even come remotely close to the Nikon extreme performance, at best only achieving 61% resolution of the Nikon's best extreme resolution performance. Put another way, at best the Canon extreme performance is still only 82% the worst performance of the Nikon at its extremes.

Let me restate that: the best the Canon lens is capable of at the extremes is still only 61% of the best the Nikon lens is capable of at the extremes (2750^2/3500^2 LPPH).

61%. Sounds pretty close to 50%. Half the resolution, people.

Are my qualitative pictorial examples still so unbelievable? Science! It works!

But feel free to take my pictorial results that appear to, qualitatively, directly reflect photozone's quantitative findings with a grain of salt... or, better yet, do your own tests :) Of course, if edge-to-edge sharpness has not bothered you in your own shots/printing workflow, then perhaps this is all entirely irrelevant to you!

Even DxO is controversial.
No, it's not. Not if you know what DXO is actually doing.

If you don't believe them/me, do the tests yourself (as I did). My numbers in my own lab setup with a 13.2 stop transmission step wedge agreed with DXO within 0.3EV. Not to mention real-world comparisons that showed that I could underexpose an image 8x (3 stops) on a D7000 & still get its shadows to look better, pushed 3 stops, than a 5D Mark III image exposed properly.

I still shoot Canon (for reasons I don't wish to enumerate here). But I'm not blind to the obvious, which is why I use a Nikon 14-24 on my Canon 5D Mark III (for landscapes).

Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 17, 2012, 01:01:47 AM »
... there are a ton of reviews on both of these lenses, much more in depth than this one photo taken at different settings can ever provide.

How were my photos taken 'at different settings'?

Go to photozone.de for a starter.

Yup, photozone's numbers are great, & I'm a firm believer in quantitation. But side-by-side images can sometimes tell you what those numbers mean in your imaging system. Which is why I performed the test on my own to begin with. It's just one way of representing the data, & was particularly helpful to me anyway.

Lenses / Re: Canon EF 14-24 f/2.8L [CR2]
« on: June 16, 2012, 09:57:04 PM »
though I don't feel that even the center Canon shot you posted is tack sharp or any representation of what the lens is capable of, I have this lingering hunch that somethings altogether are off in both images...

Yeah I'm not sure how to respond at this point either, since that center crop is pretty much as sharp as I see for any lens at an ACR sharpening setting of 25 (default). I have a feeling you're not liking it b/c of the flare... but I just sent you a PM w/ both RAW files, so you can sharpen & adjust contrast to your heart's content :)

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