ProfHankD

ProfHankD

Lives in United States Lexington, United States
Works as a Professor
Has a website at http://aggregate.org/hankd/
Joined on Mar 27, 2008
About me:

Plan: to change the way people think about and use cameras by taking advantage of cameras as computing systems; engineering camera systems to provide new abilities and improved quality.

Comments

Total: 980, showing: 61 – 80
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In reply to:

ProfHankD: That "decoupling the shutter angle of capture from the shutter angle required for artistic effect" sounds like they've been reading my research papers on TDCI (time domain continuous imaging). :-)

Interesting that they are saying "755 RAW megapixels"... I guess they've given up on calling them megarays. Probably a good idea too.

Rishi: The "shutter angle" analogy is for the cinema folks. What I've been publishing for several years, and Lytro now seems to want to do, is to synthesize different framerates by stacking faster shutter speed exposures. Yeah, you pretty much can average frames if the temporal gap is small or exposures are temporally skewed (my preferred approach converts to a continuous waveform representation and samples that); this is also how you get HDR despite high framerates. Take a look at my Electronic Imaging 2016 paper overview slides: http://aggregate.org/DIT/EI2016/ei2016TDCI.pdf

Also at EI 2016, Ng talked about a Lytro 164MP APS-C sensor. 755MP could be a bunch of those with overlap and processing? Of course, my original TDCI design target was a single 4x5 sensor (segmented solar cell) with 500MP and equivalent of over 1000FPS, so something like that is possible too... or it could just be many conventional cameras in a plenoptic array.

Link | Posted on Apr 12, 2016 at 02:30 UTC

That "decoupling the shutter angle of capture from the shutter angle required for artistic effect" sounds like they've been reading my research papers on TDCI (time domain continuous imaging). :-)

Interesting that they are saying "755 RAW megapixels"... I guess they've given up on calling them megarays. Probably a good idea too.

Link | Posted on Apr 12, 2016 at 00:03 UTC as 52nd comment | 9 replies
On article Crossing the Bridge: Canon XC10 Review (261 comments in total)
In reply to:

Michael Ma: I think the likely reason this camera doesn't do RAW is because they are afraid that it might get hacked and it might start shooting RAW videos. I just don't like the intentions behind the reason. It's just terribly not in favor of the customer.

Also, for the skin tones test of the samples, the skin was underexposed. Good luck fixing that in lossy 8-bit.

I bet the lack of raw is because that lens is doing some nasty stuff that they fix in firmware postprocessing.

Not having raw actually increases the motivation for somebody to hack it, but this is enough of a specialty that I doubt it's a priority for anyone to hack. I see no mention of it at the CHDK wiki nor at Magic Lantern.

Link | Posted on Apr 9, 2016 at 02:14 UTC
On article Crossing the Bridge: Canon XC10 Review (261 comments in total)

This isn't really a 4K camera... it's an outstanding 1080 that lets you master in over-sharpened, artifacted, 4K. That's actually fine; there's a market for that. As for being a bridge, well, that's truly a stretch....

Minor points: For "Slow and Fast motion capture," 720 @120FPS isn't awesome slow motion these days and I don't see any fast motion framerates unless 24FPS counts for that. Also, a "2x Digital Teleconverter" isn't gonna get you 4K on a 12MP sensor.

Link | Posted on Apr 9, 2016 at 01:33 UTC as 40th comment
In reply to:

Felipe Rodríguez: I don't know you, guys, but I'm not impressed by the sample images. Firstly, they don't remind me of the daguerrotype look at all (of course, and assuming the optics are similar, they are only a part of the daguerrotype process). Secondly, I don't like those quirky aperture effects. So, even if I am keen on trying (and somehow collecting) strange and special lenses, I think I won't be tempted by this one...

AiryDiscus: Not familiar with stop shift theory (the slides didn't quite do it for me either), but I'm certainly aware that position of the stop can play a huge role in controlling aberrations. Is coma the primary cause of the off-axis smearing in the wide-open images? I wasn't sure, although there is definitely a lot of badness going on.... Then again, isn't f/2.9 a real push for this type of lens?

Link | Posted on Apr 7, 2016 at 20:54 UTC
In reply to:

Hartmonstr: That's what I'm talkin' about, Hasselblad! As a user since 1974 (and current H5D-50c owner) it's nice to see the company doing what it's always done best - creating state-of-the-art tools for users who can appreciate and make use of their capabilities.

Welcome back, Hasselblad!

It might still be too expensive for me to buy, but at least it's a product I wish I could afford. ;-)

(Although I still wish they'd actually do a medium-format sensor -- the 100MP is really 4:3 aspect ratio cropping to a 4x4 square format at 75MP. Basically, that's a 1.5X crop factor off 6x6.)

Link | Posted on Apr 7, 2016 at 15:37 UTC
In reply to:

Felipe Rodríguez: I don't know you, guys, but I'm not impressed by the sample images. Firstly, they don't remind me of the daguerrotype look at all (of course, and assuming the optics are similar, they are only a part of the daguerrotype process). Secondly, I don't like those quirky aperture effects. So, even if I am keen on trying (and somehow collecting) strange and special lenses, I think I won't be tempted by this one...

Basically, this is an even more questionable step in the direction of pretend emulation of old lenses. Basically, the defects of lenses don't really scale from larger formats to FF or APS-C. Actually, this lens is particularly funky in that 75% of the front is empty barrel... and I suppose having a built-in hood helps, but really. There is also the cute little comment about how the Waterhouse stops are better here because they don't go between the lens -- but how could they go between elements in a simple achromat?

Anyway, they've met their funding goal, so, I guess it will happen.

PS: Interesting how many of the "sharp" images missed focus. Oh well. I guess it is hard to precisely focus a smeary image on a DSLR without any manual focus aids. ;-)

Link | Posted on Apr 6, 2016 at 20:56 UTC
In reply to:

brazzy: DO NOT FLY DRONES ABOVE CROWDS. NEVER.
I do not know about FAA rules, as I don't live in the US, but this is the first unwritten requirement that every operator should have in his mind.
Mr. Johnson did something very good by going at dawn on Friday to take his footage, then something very wrong by flying above people on Saturday afternoon. He has been unlucky he couldn't get what he wanted on the very first time, but hey, this happens to all landscape photographers.
I am not against drone photography and I appreciate his work. I fly my Phantom 4 in Tokyo area and I get the same smooth videos - it works just great. But it's just too dangerous, you never know what may happen: Phantom 4 is reliable but the unexpected is always behind the corner.
I do hope that watching this beautiful video and picture won't stimulate other people to do the same. Dpreview should be careful about promoting this kind of footage.
DO NOT FLY DRONES ABOVE CROWDS.

Brazzy is right -- the FAA makes it very clear that flying over people is generally NOT ok, but police don't really have clear legal grounds to say no. The first shot looks like it might be violating commercial airspace -- if the university has a hospital (as mine does), they have helicopters land/take off, and drones are required to keep away from air traffic and airports. Some of my colleagues here at the University of Kentucky are doing research involving drones, high-altitude balloons, and even orbital systems -- getting permission is complex, and complexity increases with altitude.

The issue is not really immediate danger from one drone, but establishing guidelines that will work when LOTS of drones are flying. The registration deadline was Feb. 19 (I registered mine), and it's very clear they're still trying to figure-out the rules. I expect there will eventually be many classes of drones with various restrictions and licensing procedures....

Link | Posted on Apr 4, 2016 at 06:05 UTC
In reply to:

darngooddesign: This is great. I used a similar guide to replace the lens module in my S100 after it developed the lens error. This looks like a less fiddly and easier repair than that was.

Wow... all that and the lens drive still is not accessible! The most common problem with Canon PowerShots is the "lens error" due to a stripped plastic gear on the lens extend/retract drive... which looks like it would be an utter nightmare to repair for this. You know, repair of a stripped gear shouldn't require replacing the entire lens assembly....

Link | Posted on Apr 2, 2016 at 18:05 UTC

Doesn't look like a particularly clever method to me; lots of issues -- including a much larger (longer) hump and projecting a backlit LCD seems grossly inferior to projecting an OLED display. However, it does look like they could just stick it on the back of an EVF without having to redesign the camera guts... which I'm sure Canon would consider to be good, because they rarely make significant changes to the guts.

Link | Posted on Apr 2, 2016 at 02:27 UTC as 15th comment
On article Hands on: Sony FE 50mm F1.8 and 70-300mm F4.5-5.6 (137 comments in total)
In reply to:

RStyga: The 50/1.8 looks large, not to mention the tele zoom; not sure that the mirrorless design helped here.

For what it's worth, the 50mm f/1.8 MTF graph actually looks a lot closer to that Sonnar T* FE 55mm F1.8 ZA than to the Canon 50mm f/1.8. In fact, this Sony really outclasses the Canon by significantly more than the Sonnar beats it. More importantly, it probably beats a lot of old fast 50s pretty cleanly -- and nearly every fast 50 IS the competition it has to play against. I think this will put an end to the LA-EA4 + Minolta Maxxum AF 50mm f/1.7 combo as the default cheap, fast AF, normal for FF E mount bodies. :-)

Link | Posted on Mar 31, 2016 at 20:23 UTC

Good to see the 960FPS video mode continue. This was rumored to be coming on various E-mount bodies, but I'm still waiting....

Link | Posted on Mar 30, 2016 at 02:25 UTC as 23rd comment
On article Hands on: Sony FE 50mm F1.8 and 70-300mm F4.5-5.6 (137 comments in total)
In reply to:

peeyaj: The 50mm f/1.8 is seriously tempting and at $249, will quell the complaints of FE lenses having no cheap options.. Good job, Sony.

Yup. Here's the "kit prime" for the A7 family.

Link | Posted on Mar 30, 2016 at 02:17 UTC
In reply to:

gianstam: Fortrunatly Nikon cares about its (pro) target group and not about DPR forum members

It's not just a matter of DR, but of how many shades per stop -- tonal resolution. The truth is you can get away with as few as about 32 distinct shades per color channel (5 bit DACs used to be the standard) and still have a display look good -- but you're not going to get 32 cleanly distinguished shades out of a lot of slightly-pushed exposures with this camera. That's disappointing. Beyond that, the ultra-high ISO settings on this camera are a bad joke -- truth is, there are barely enough photons for decent tonal quality by ISO 6400 at this pixel size (although good computational processing can hide that fact pretty well).

Put simply, Nikon has done a lot better than this. I'm sure it is still a fine camera overall, but the question is why did they decide to do this AND to simultaneously pretend this is a low-light record-breaker?

Link | Posted on Mar 29, 2016 at 10:58 UTC
In reply to:

eno2: Very nice, thank you for the test!

I agree with everything you said except the part about the "more sophisticated" Sony JPEG engine:
"When it comes to JPEG, Nikon (and Canon, for that matter) have some work to do with respect to optimally balancing sharpening and noise reduction in JPEG, as detail in the Raw is left on the table at both low and high ISO sensitivities compared to Sony's more sophisticated engine."

I strongly believe the Sony JPEG engine is one of the worst there is out there! Full of ugly looking artifacts (from a bad NR + sharpening) and terrible colors.

I think Sony was actually ahead on JPEGs for quite a while before they obviously looked better. The catch is that they favored getting a high dynamic range first, and that increased visible noise; now, their sensors have very low noise and they are remarkably good at reducing noise further in the JPEG engine. Sony sharpening might be a little overly aggressive, but it doesn't produce artifacts -- just sometimes synthesizes detail where it wasn't. ;-)

Link | Posted on Mar 28, 2016 at 18:42 UTC
On challenge ND, or not too ND? (6 comments in total)

Well, at least there are two entries....

I guess this goes on to my short list of things to really test for a research paper to Electronic Imaging 2017.... ;-)

Link | Posted on Mar 24, 2016 at 01:58 UTC as 2nd comment
On challenge ND, or not too ND? (6 comments in total)

I'm disappointed that you're the only one who has submitted so far, but yours is a nice entry. This is one of those tricks I thought people would really appreciate, but maybe not so much? ;-)

Link | Posted on Mar 22, 2016 at 04:28 UTC as 4th comment | 1 reply
In reply to:

Revl: Hi Everyone. Thank you for your questions and concerns. We have made a new video to answer all of your questions.

https://youtu.be/wVd941tLPIg

steve ohlhaber has the right idea. Most footage shot from a GoPro without a stabilizer is pretty useless.

We stabilize all of your video in real time BEFORE it is recorded to the SD card.
No post Stabilization required!

Just trying to get some facts straight. Cheers!

Ok. So 1 motor rotational control + sensor-data-driven "electronic image stabilization" implemented by computation in the video pipeline. Sounds reasonable... without rotation, it's basically parametric lens distortion processing using the sensor data to tweak the parameters, right? Good trick.

Link | Posted on Mar 20, 2016 at 15:18 UTC
On article Adobe Camera Raw 9.5 introduces new color scheme (127 comments in total)
In reply to:

matthew saville: Haha... For a fraction of a second, I thought that "color scheme" might possibly be some sort of new processing profile that better matched my in-camera colors, but no. They changed the *skin* of the ACR interface. Yay.

>> What specifically isn't native raw sensor data?

The color basis function and CFA pattern, dark reference, pixel aspect ratio, DNG data format specifiers, etc. There's a lot of EXIF info needed to decode a DNG. There's even more potentially useful, from shutter speed to battery temperature, face-ID regions, etc. Take a look at EXIFTool to see what a mess this stuff is....

The problem for DNGs is that there are lots of alternative fields with slightly different ways to say the same things, and various DNG-processing tools assume they come in specific (proprietary/undocumented) groups. ADC does a good job of copying a lot of EXIF data into all potentially-relevant fields (e.g., it copies the "Shutter Speed" field into the "Shutter Speed Value" field), but things like color info get encoded very differently and the original fields are not passed-through. Some are changed a little: e.g., "Blue Balance" was 1.5 and became 1.496094? Maybe that's how some pixel VALUES change too?

Link | Posted on Mar 18, 2016 at 21:21 UTC
On article Adobe Camera Raw 9.5 introduces new color scheme (127 comments in total)
In reply to:

matthew saville: Haha... For a fraction of a second, I thought that "color scheme" might possibly be some sort of new processing profile that better matched my in-camera colors, but no. They changed the *skin* of the ACR interface. Yay.

>> All that is necessary is the actual/all raw sensor data, NOT proprietary metadata. DNG provides exactly that sensor data.

Again, DNG can, but Adobe DNG Converter generally provides only the info Adobe wants and in the format Adobe wants it. If Adobe DNG Converter did preserve everything, it would be trivial for the native-raw-to-DNG transformation to be reversible: Adobe very clearly states it isn't.

To reliably see pixel value differences, you need to look directly at the numerical pixel data in the files. I used C code implementing the logic from dcraw to walk the data structures (that's how KARWY makes repairs). Alternatively, run both original raw and ADC uncompressed output through 16-bit dcraw -E. At least for various Sony cameras, the data doesn't match... and Adobe Photoshop used dcraw as a reference, so guess which I trust to be right? ;-)

Link | Posted on Mar 18, 2016 at 20:15 UTC
Total: 980, showing: 61 – 80
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