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Messages - dgatwood

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1
Lenses / Re: Canon APS-C<Speedbooster<EF Lens. Possible?
« on: September 24, 2014, 01:21:08 AM »
Yes it cannot be physically done. Every lens is designed to project the image on a specific distance (distance from lens to sensor), this is called the flange ditance. Now when you put an adapter or a speedbooster, the lens will be pushed away from the sensor and will not be focusing on its correct plane.

Well, you're partially right.  That makes it harder, but not impossible.  With a teleconverter, the lens gets farther away from the camera, but the focal plane shifts backwards by the same amount.  With a wide converter, the focal length is reduced, so without additional correction, you'd have to somehow move the sensor closer to the lens, which is impossible (obviously).  You can, however, compensate for that by adding extra optical elements that shift the focal plane further away.

The good news is that Kodak actually designed a telecompressor a couple of decades back that did exactly that.  The bad news is that they patented it, and the patent (US5499069) didn't expire until four months ago, which is a big part of why such devices aren't on the market today.  From the patent claims:

Quote
1. c) an optical adapter located between said lens barrel and said camera body for providing a smaller size image than said objective lens system provides when mounted directly to the camera body, said optical adapter including a lens attachment optical system, a front lens element of which is located in front of an image formed by said objective lens system exclusive of the lens attachment optical system, said lens attachment optical system having a plurality of lens elements which have radii of curvature and spacings sufficient to create a back focal distance to clear the SLR camera body mirror.

Emphasis mine.

More to the point, Kodak's patent covers only situations where you have to maintain a long back focus (flange focal distance).  Wide converters that adapt lenses with a long flange distance to cameras with a shorter flange distance aren't affected by that patent, which is one reason that they're readily available.  (That, and they're a lot easier to design.)

Now that the Kodak patent has expired, it seems fairly likely that we'll see these appear on the market in the not-too-distant future, assuming anybody is willing to spend the time to design the (significantly more complicated) optics.


2-the lens must be designed to cover a larger sensor than the camera's sensor it's being used on, for example, a full frame lens on an APS-C body, because the idea of a SB is that it focuses the large image circle down to a smaller circle, giving an increase in light density and wider fov. If you use an APS-C lens with a SB on an APS-C body, the SB will shrink the image circle of the APS-C lens to a smaller m34s-ish image circle, therefore you will have a huge viggentte.

This part is correct.  The only way to avoid that is by putting a wide-angle adapter on the front of the lens, rather than the back, which is generally undesirable for any number of reasons.  :)

2
EOS Bodies - For Stills / Re: POLL: What's more important, gps or wifi?
« on: September 23, 2014, 04:42:04 PM »
I don't want or need WiFi but I understand the use for it so I won't begrudge anyone who wants it. As for GPS, I'd want that but we've all seen how poor Canon's GPS implementation has always been. Craptastic at best.

Really?  GPS on my 6D works pretty darn well, from what I've seen.  Their Wi-Fi implementation, on the other hand... is craptastic.


What I'd really like to see is Direct transfer of files via USB to my smartphone. Phones can get 128GB of MicroSD storage and have beefy quad-core CPUs, so why not?

You can do that with an iPhone right now.  You'll just need a Camera Connector Kit and a USB cable.  The reason some of us like Wi-Fi is that all you have to do is turn it on, wait for your phone to find it, and suck the images across, without carrying extra stuff with you.


It would certainly be faster than WiFi. Another option would be USB2Go drives that could plug into a Canon camera and the camera would transfer the files to the flash drive.

That would be easy enough for Canon to add, given that I'm pretty sure they already have a USB host controller inside the device.  With that said, I'd be curious how many people would take advantage of it—again, it's another piece of hardware to carry around.

3
EOS Bodies - For Stills / Re: POLL: What's more important, gps or wifi?
« on: September 23, 2014, 12:40:41 AM »
Agreed.  I'm more than a bit fed up with Canon's absurd little game of haphazardly putting different random subsets of features in each of their cameras.

Cannot will agree to this :-)

If they had it their way, it would be like in the good ol' times just xxxd (joe sixpack) - xxd (enthusiast) - 1dx (sports) + 1ds (studio).  Given this alternative, I'm rather happy with Canon's feature juggling because that's the only way they dared to produce a ff 6d I can afford :-o

You know, it is possible to differentiate based on features without being haphazard about it—to put everything in the high-end bodies, and fewer and fewer features in the cheaper ones—you know, like every other hardware manufacturer in the universe does....  :D

Instead, Canon stuck most of the wireless toys in the 6D—right in the middle of their lineup—and there's fewer features in everything else, whether it costs more (5D Mark III, 1DX), less (70D), or about the same (7D Mark II).  It's like somebody pulled out a dartboard, taped features to it, and threw darts to see what would go where.  It really makes no sense.

I guess to be fair, the 5D Mark III and 1DX are a bit older, so if they add GPS and Wi-Fi in the next update to those bodies, their lineup will seem a little less random and more sensible, but right now... it's just bizarre, particularly with the 7D Mark II leaving out Wi-Fi.

4
EOS Bodies - For Stills / Re: POLL: What's more important, gps or wifi?
« on: September 21, 2014, 10:32:19 PM »
In 2014 I only consider Canon cameras with all 4 radio modules built-in. No excuse tolerated.

* WiFi (b/g/n and ac)
* GPS
* NFC
* RT-EX radio flash commander

Since Canon is not willing and/or able to .. I will not buy anything from them. It's that simple.

Agreed.  I'm more than a bit fed up with Canon's absurd little game of haphazardly putting different random subsets of features in each of their cameras.  It can't be expensive enough for this approach to make sense.  Just put all the radios in every device already, and declare yourselves to be the first camera company to have GPS, Wi-Fi, and RF flash control in all your cameras.

(I don't particularly care about NFC.  All that does is make it slightly easier to pair the camera with some cellular phones.)

5
EOS Bodies - For Stills / Re: Which Canon L Lens for 7D Mark II?
« on: September 21, 2014, 10:26:46 PM »
I am about about to upgrade from my Canon T2i to the 7D Mark II.

Makes no sense. If you want a real difference in the outcomes, go FF and save the money you'd first waste on a 7D2.

Agreed.  You don't need an insane amount of reach for weddings, and you don't need ultra-fast focusing (unless it's a very unusual wedding in the middle of a basketball court during the game or something).  What you do need is great low-light handling.  A 6D would be a much better choice, IMO.

And although the 6D's AF system gets a bad rap, it really isn't that bad.  I shot a bunch of shots at a basketball game with mine just for fun, and although it didn't nail focus on every single shot, it nailed enough of them that I found it to be more than good enough (or at least good enough for someone who wasn't getting paid to get a specific shot).  :)

6
EOS Bodies - For Stills / Re: POLL: What's more important, gps or wifi?
« on: September 21, 2014, 10:12:51 PM »
Hopefully Canon and any other camera manufacturer is implementing the possibility to switch those gimmicks OFF.

Of course you can switch off wifi & gps (the 6d has even a wifi indicator on the top lcd which is a complete waste of space). The catch with the 6d and probably 7d2 is just that gps stays on on camera off to continue the track log - so you have to remember to switch it on/off manually each time (or use Magic Lantern).

AFAIK, the camera doesn't actually save a track log unless you tell it to do so.  But it does continue to have the GPS hardware update its position on a regular interval, in part because the GPS ephemeris data is only valid for a certain period of time (typically four hours), and if it gets stale, reacquiring a GPS lock takes much, much longer.  And, in part, because actually acquiring a GPS position, even in hot start mode, would unnecessarily delay writing photos out to flash (by 1–5 seconds, depending on hardware), and they probably don't want to bother going back and rewriting the images after GPS data becomes available (even though they really should).

7
Lenses / Re: Does it matter anymore who makes the sensors?
« on: September 21, 2014, 09:56:10 PM »
I'm unconvinced that innovation would being stifled - whether Sony was the single source or not, I assume they would want to sell more sensors. This means their customers need to offer better imaging performance which - to the extent that the sensor dominates things - means the sensors need to develop.

To play devil's advocate, if they have no one to compete against, then they could much more easily drive sales though planned obsolescence, and make higher profits without all those pesky R&D expenses.  :)


Being held to ransom - well that's what contracts are for. So that's nonsense too.

Assuming innovation doesn't stop, those contracts get renegotiated for every subsequent sensor.  The problem with buying parts from a highly vertically integrated company that competes against your products is that they have every incentive to charge more money to their competitors than to companies that don't compete against them, to make up for some of their losses.

Right now, Sony isn't the only company building sensors and making them available to third parties, so there's competition in that market.  If that ceased to be the case, Sony would probably crank up the price for Nikon and other companies whose products compete with Sony's products.


There is risk because Sony could close their fab plant... Struggling companies do not close or sell business units that make money. If it's a profit centre, it is safe. This feeds back into my first point - to continue making money, Sony needs to continue selling sensors which means more innovation.

The bigger risk is a manufacturer choosing to focus their R&D on parts for a different, more profitable area.  For example, right now, Sony's sensor division reluctantly builds big sensors for companies like Nikon, in part because they use them in their high-end camera gear.  But Sony could decide to scrap or sell off that division tomorrow, and to focus their sensor R&D on cell phone camera parts whose high volume makes them a better, more reliable profit center than broadcast video gear.  If that happens, Nikon would be seriously screwed.


On the different "look" offered by various cameras - I think this is bogus too. Most on the forum will know how to change the colour mapping. (If not, download Lightroom and move the sliders around or look for a preset.) Secondly, a lot of Canon's "warm look" arises from the lenses. If you switch to Zeiss glass, suddenly your images are quite cool.

I agree that it's mostly math.  There's a caveat, though; in some cases, there may be differences that can't readily be compensated for, particularly between sensors that have different combinations of color components, where entire parts of the color signal are not captured at all.  This is particularly likely to be a problem when dealing with fluorescent light or, to a lesser degree, LED light.

8
Lenses / Re: Does it matter anymore who makes the sensors?
« on: September 21, 2014, 09:26:57 PM »
I've been shooting with Sony video cameras for the better part of 30 years from the original Betacam to their current FS700, F55 and XDCam. I've always felt Sony imagers had a cold look to them. We were always trying to find ways to trick the cameras to produce a warmer image. We'd use 810 filters, warming cards, putting a piece of 1/8 CTB gel over a white card, etc.. When Panasonic came out with their Varicam, SDX900, HDX900 their imagers had a much nicer, warmer image than Sony. I feel the same with Canon sensors. They have a much more pleasant look right out of the camera vs Sony. I've got a 5D2 right now with some nice L glass Hope to get a 5D3 at some point. I've used the Canon C500 and will be using a C300 tomorrow and Tuesday. Love the look of the Canons. Like you said, they have a Kodachrome look to them. Not complaining about their sensors, just making an observation. I'm happy with my 5D2 and lenses. I've been a Canon guy since the late 1970's. I'll never buy Nikon. I really like the color rendition of my 5D2 over my friend's D800. I don't get into the weeds about pixel count, DR etc.. I look at the picture and if it looks good to me I like it.

Curious.  In consumer camcorders, I always found Panasonic to be very cold, with Sony right in the middle, and Canon on the warm side.

9
Nikon D810 uncompressed RAW, 12-bit: 55.9 MB
Nikon D810 uncompressed RAW, 14-bit: 73.2 MB

That's a file size increase of ~30% going from 12- to 14-bit. 

I wonder why.  Mathematically, I'd expect it to be only about a 17% increase.  I wonder if they're doing something lame like using 16 bits instead of 14 to save on CPU bit shift overhead....  :)

Edit: 55.9 / 12 * 16 = 74.53 MB, so when you factor in the fact that part of it is a JPEG preview, EXIF data, etc. that doesn't expand, I'd say it's pretty likely that they're really writing it out as 16-bit data.

10
But given that Canon's 1DX doesn't have more than 12 stops of DR and that stops of DR are bits then it even seems pointless for Canon to have 14bits of raw, don't you agree?
It's quite a lot of colour-information in those 2 bits, not just DR.

AFAIK, each RAW pixel value is actually the value of a single-color subpixel.  The physical location of that subpixel determines what color it is, based on what color filter is in front of that subpixel.  So a 14-bit RAW pixel value is literally just a black-and-white (well, red-and-white or blue-and-white or green-and-white or whatever) value telling the amount of a single color.

BTW, where do you get 12 stops of DR?  By my count, it would take 17 bits (well, slightly more than 16) to properly represent the full well capacity of the 1DX sensor at low ISO.  That should mean that it has >16 stops of DR.

11
EOS Bodies / Re: 7D2 and EF 24 - 105 F4 L IS USM
« on: September 20, 2014, 02:40:17 PM »

The 24–105L really doesn't seem like a good match for a crop body.  Unless you're planning to upgrade to full-frame in the next couple of years, you're probably better off with a 15–85 as a general shooting lens.  It's sharper than the 24–105L, and it's a more useful focus range.

On the other hand, if you already have a 24–105L, then the best lens is the one you have with you.

12
EOS Bodies / Re: Will Canon answer Sony's new cinema cameras
« on: September 20, 2014, 02:15:10 AM »
Canon's XF Codec is already integrated into a lot of company's workflows. Very few channels broadcast 4k and it's very expensive to post in 4k.

That's why you acquire in 4K, post in 1080p, and keep the original 4K assets for future-proofing, much like many studios did with 16:9 content during the first part of the last decade, when most TV sets were still 4:3.  Then, when you need 4K versions of the content, you import the EDLs, pull in the 4K assets instead, and bring in people to update the SFX for 4K, if necessary.  By the time you actually need the 4K content, computers will be fast enough that much of the 4K post work won't be expensive anymore.  :)


There's a market for 4k in the consumer sphere (youtube distribution), not so much in the professional sphere, that's all 1080p except at the ultra high end. This isn't a consumer device, it's a professional one, and thus it's build on reliability and integrating into conservative workflows, not specs or features alone.

Workflows, though, not acquisition.  It's very shortsighted to do content acquisition in anything other than the highest quality format you can get your hands on.  Downsampling during ingestion should be relatively easy.  If it isn't, either hire a programmer or get better editing tools.  :)


Look at how Arri is destroying Red in broadcast tv and in film... It's not because Arri has the better format (the Alexa does have a better image)... it's because it has an easier to handle, "lower end" codec in a lower resolution.

I'd imagine a big part of it is also reputation and familiarity.  Red isn't even a decade old, whereas Arri has been doing cinema hardware for almost a hundred years.  Folks know the name, and they're used to their gear.



I can do 4K natively on my Samsung Note 3, but not all 4Ks are equal, and 4K is not necessarily better than 1080p. 

Fair enough.  I didn't mean to imply that the 4K quality on a cell phone would even remotely approach that of a DSLR (or even necessarily be as good as 1080p on a DSLR).  I just meant that if a cell phone has the CPU/GPU horsepower to produce 4K output, it's embarrassing for expensive DSLRs to not be able to handle it at all.

13
EOS Bodies / Re: Will Canon answer Sony's new cinema cameras
« on: September 19, 2014, 07:33:17 PM »
No it won't. Other camera companies are already introducing 4K into their consumer product lines, so Canon doing it later would still be a dollar short and a day late.

Canon doing it now is a day late and a dollar short.  After all, with the right ($1,000) software, you can capture 4K video on a freaking iPhone 5S.  The fact that so many multi-thousand dollar DSLRs sold today can't even do what a <$100 cell phone (with 2 year contract) can do is an utter embarrassment, IMO.

It's way past time for Canon to step up their game and quit treating decent video quality as an excuse to squeeze more money out of their customers.  It's not an opportunity for an upsell anymore; it's basic functionality.

14
EOS Bodies - For Stills / Re: POLL: What's more important, gps or wifi?
« on: September 19, 2014, 04:19:23 PM »
Easy.  GPS.  Wi-Fi is easy to replace by carrying a little more gear, whereas GPS isn't.

It's a pain in the backside to geotag photos without in-body GPS.  If you use an external receiver, that's one more piece of gear that has to be continuously attached to your camera.  If you use track logs, that's one more battery to keep charged.

Also, the precision of geotagging is likely to be better with in-camera GPS, because the camera knows when you pressed the shutter, and can get coordinates at that exact moment instead of on a ten second interval or whatever.

By contrast, it's not that hard to carry around an SD card adapter for my phone (to replace one of my uses for Wi-Fi) and a radio remote (to replace the other one).  The batteries in a remote last for months, so they're a non-issue.  And although radio remotes do require a device to be attached to your camera, you probably won't need to have it attached for every shot for days on end, unlike your GPS receiver.

Also, the alternatives to Wi-Fi work a bit better than Canon's Wi-Fi implementation, IMO, albeit at a cost in terms of the amount of extra gear you're carrying around.  In particular, the EOS Remote app doesn't appear to support continuous shooting, unless I'm misusing it somehow.  And because it operates in live view mode, focusing is slow, effectively giving you a huge shutter lag.  With that said, it is still better than a timer.

15
Lenses / Re: 24-70mm II front element damage from mist
« on: September 19, 2014, 03:53:08 PM »
Good luck with it.  Don't be surprised if Canon tries to weasle out of it. All they have to do is claim that it is damage in excess and how can you, the consumer, prove otherwise?

You don't have to.  You can insist that they repair only the problem you sent it in for—the failed coating—which cannot possibly be caused by water unless the coating was fundamentally flawed to begin with.  At that point, the burden of proof falls on Canon.

To legitimately disclaim the warranty on the coating, Canon would have to claim that it is reasonable for a lens coating on a roughly $2,000 camera lens to flake off when exposed to water.  If Canon made such a claim on the record, no one in their right minds would ever buy a Canon lens again.

Obviously if (many years from now) something else fails because of water damage, that's your problem... but realistically, it probably won't.

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