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Messages - neuroanatomist

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7441
EOS Bodies - For Stills / Re: New MFA method
« on: February 04, 2013, 02:12:02 PM »
Now wouldn't that be nice... just point the camera at a target at the distance where you wanted AF fine tune to be optimized, and press a button which would do this procedure instantly and electronically. You could even re-tune your cameras for a new distance (i.e., when shooting from the back row vs. front row) in real time on the job.

I'm definitely trying it. Why didn't we think of this before? It's so obvious.

Something similar has been suggested:

In theory, it should be possible to achieve an ‘accurate’ focus using contrast detection in Live View, where no alignment is needed because the image sensor is used to determine best focus, then compare that to the phase detection AF and correct accordingly. In practice, this is something that’s difficult to do (because the act of moving the focus ring to see if you were really optimally focused changes the focus, and you lose the ‘zero point’). However, this is an idea that Canon could implement as a semi-automated routine, i.e. set up and align target (Canon could sell one, and suitably overcharge for it as they do for other small pieces of plastic *cough*), then the camera automatically determines the optimal adjustment. File that one under ‘gee, wouldn’t it be nice…’

Using AF Confirmation for manual focus to avoid having to move the focus ring is a nice solution!

7442
Lenses / Re: Resistance to Larger Filter Size, Kills Great Lenses?
« on: February 04, 2013, 01:04:47 PM »
Could someone explain why these specs indicate a need for 95mm filters? As far as I can tell, a 82mm thread would be enough...

They don't, necessarily.  But if you look at the 24-70 (both verisons), the front of the lens has a ring of reasonable diameter (sufficient to print the lens ID info) around the front element, meaning the filter diameter is a fair bit larger than the front element.  Not all lens designs have that much space (and some have a lot more). 

Does Canon have a reason for designing it that way? Probably.  Note that a quick comparison of this image suggests that the front element of both versions of the 24-70L is pretty close to the same size, but the MkII uses an 82mm vs. a 77mm filter.   Reasons could be to reduce chances of mechanical vignetting with a filter in place, to allow space for a more robust bracket setup to hold the front element, etc.

7443
EOS Bodies - For Stills / Re: Canon 6D for BIF
« on: February 04, 2013, 12:47:25 PM »
I can't speak from experience with the 6D, but based on the AF system, it's not going to be optimal for BIF.  A higher density of AF points, along with an expansion mode where the nearest point is used if the subject drifts off the selected point, make tracking a BIF much easier. 

Certainly, a 6D can be used for BIF.  People shot BIF with manually-wound film cameras before AF lenses existed...  But with a 5DIII, the camera will do a fair bit of the work for you, whereas with the 6D, it'll be mostly down to your skill. 

7444
Lenses / Re: Is the 70-200 f2.8 IS USM II rebate still on? ...maybe...
« on: February 04, 2013, 11:33:25 AM »
Amazon often lags behind in changing pricing for rebates.  That happens at both ends - when I bought my 7D, I wanted to buy through Amazon since I had a few hundred $ in gift card balance - thanks to a post here on CR, I was aware of a $100 rebate the day before it went into effect, and the next day I went to buy but the rebate had not been applied.  I called Amazon, they verified the rebate and applied a discount to my order, but their website didn't actually reflect the rebate for another day. 

Also note that even post-rebate, prices didn't go all the way back up.  For example, the $400 rebate on the 5DIII+24-105 kit ended, and the B&H in-cart price went up only $100, from $3500 to $3600.

7445
EOS Bodies / Re: Canon Confirms 70D; Future of Semi-Pro DSLR is FF
« on: February 04, 2013, 10:30:31 AM »
The other problem is the mirror. EF-S lenses use the space that was freed by the smaller mirror for APS-C. I think there also would not be enough space for an APS-H mirror. But, you are free to use third-party APS-C lenses (Sigma, Tamron) even on a FF Canon Body, and crop it on your own.

Exactly.  First off, the lens mount would have to be modified - there's a part of the mount of EF-S lenses designed to prevent them from mounting on EF mounts.  If you physically remove that part of the mount on a lens like the EF-S 10-22mm, you can mount it on an APS-H body like a 1DIV - if you restrict yourself to the 12-22mm range, it's fine, but at 10mm the mirror hits the back of the lens. 

Could Canon, in theory, design a mirror that doesn't have this issue?  Likely - there could be a translational motion in addition to the rotation, so the mirror could move back as it flips up, for example, and clear a protruding EF-S lens.  But frankly, this would just create confusion, IMO, and won't happen. 

A 7Dii has a value proposition problem.  Go back a few years and there was a big performance difference (AF, FPS) between the 7D and the 5Dii, and buying a 7D made a lot of sense to people who didn't want to step up to a 1D4.  But the 5Diii narrows the performance gap considerably.  And given the overall IQ benefits of the 5Diii, I have doubts that there would be many, if any, 7Dii buyers out there.

But the 5DIII sells for $3000...  So, a 7D in the price range of a 6D, with APS-C but the performance features of a 5DIII (lots of AF points, many cross type, high FPS, etc.), would 'force' consumers to choose between a FF sensor and high performance, or step up $1K to the 5DIII.  I think that would sound like a profitable situation to Canon.

7446
Lenses / Re: Resistance to Larger Filter Size, Kills Great Lenses?
« on: February 04, 2013, 06:48:40 AM »
Canon experimented with 2 different possible image stabilized f/2.8 zooms. There are patents for them available on both Canonwatch.com and egami.com, and canonrumors.com

Just did a search on the USPTO/google patent and there are no patents for anything related to a 24-70 f/2.8 IS. Loads of references to the 24-70 f/2.8 MKII and 24-70 f/4 IS. It could not be published yet, but I want to see the source material from the websites as nothing shows up in searching on them.

RMC33 - Your Google-fu is weak, Grasshopper.  ;)

Radiating - Thanks, although a link would have been helpful.

http://www.canonrumors.com/2012/07/patent-canon-ef-24-70-f2-8l-is/

7447
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 04, 2013, 06:08:40 AM »
So for HTP at ISO higher than base ISO negative exposure compensation could be done just by reducing analog circuit gain.
But at base ISO this might not work...

In fact, that is precisely the reason that with the HTP function enabled, the user cannot set the camera to ISO 100 (although technically, that's not really base ISO, which is in the ISO 70-80 range).  When HTP is enabled, ISO 200 is the lowest user-selectable ISO, so the camera is able to reduce analog gain by one stop at any user-selected ISO setting (the expansion ISOs where digital gain is applied post-ADC are also unavailable).

7448
Lenses / Re: Good telephoto option for birds.
« on: February 03, 2013, 11:43:14 PM »
Not on my iPhone...   ;)  The ISO 12233 crops at TDP will show the differences.

7449
Lenses / Re: Which Zoom lens?
« on: February 03, 2013, 11:40:43 PM »
The 70-300 non-L is weakest from 200-300mm.  The 70-200/4L non-IS delivers very good IQ.  Even cropped to the FoV of a 300mm lens, the 70-200/4L will deliver better IQ.

7450
Lenses / Re: Good telephoto option for birds.
« on: February 03, 2013, 11:28:24 PM »
The 100-400 is not as sharp as the bare 70-200 II - but then, very few zoom lenses are.  My 100-400 is slightly sharper than my 70-200 II + 2xIII.  If you didn't already have the 70-200 II, the 100-400 would be a good choice (if you found the one you borrowed soft, it might be a copy issue or need AFMA).  But you'd do fine with the 2xIII on the 70-200 II.

7451
Lighting / Re: Help for Speedlight MT-24 EX / 600EX-RT
« on: February 03, 2013, 11:23:22 PM »
I was not aware of that. MPE filter thread is 58 and the MT24-EX fits it. The 100 macro is 67 so you lose a little on the outsides of that lens. Or is there something else I'm missing?   

The front element of the 100L is smaller than the 58mm ring of the macro flashes, so there's no issue.  There's also a Macrolite 72 for the 180L Macro (also works fine), and even a Macrolite 58 for lenses that lack the groove for the twin/ring lites.  Personally, I use the 58 adapter with the MP-E 65 - I have a B+W MRC UV filter on the lens (for protection - I routinely shove the front of the lens into bushes), and the adapter screws onto the filter so I can mount the twin flash but keep the filter close to the front element.

7452
Site Information / Re: Moderators: You are Too Sensitive
« on: February 03, 2013, 09:58:24 PM »


Indeed, and while I guess US law would apply to CR
Nope, CR is in Canada.   Those who post are responsible for their own posts, but the moderators try to make it a plesant place to carry on reasonable conversations about photography.
They even let some of the US citizens like Neuro and myself post here.  My son was born in Toronto and has a Canadian father, so I guess that makes me part Canadian - eh :)

...and my mom was born in Regina and is still a Canadian citizen with permanent resident status in the US.  Maybe we should start a conspiracy theory about a requirement for a 'Canadian connection'...   ;)

7453
EOS Bodies / Re: EOS 70D is Coming, The Future of Pro APS-C is Unknown
« on: February 03, 2013, 08:41:58 PM »
dare we dream - f/8 AF on the center point.

I hadn't dreamt of that yet, since I just assumed it would remain exclusive to 1-series bodies. But that would be pretty cool.... I will start dreaming.

Canon announced that the 5DIII will get f/8 AF with a firmware update due out in April.

7454
Lighting / Re: Help for Speedlight MT-24 EX / 600EX-RT
« on: February 03, 2013, 06:32:55 PM »
And by the way. I doubt you will have success mounting the MT-24EX on the 100L IS. I had that flash, the MP-E65 and I own the 100L IS. It would not fit but I never tried getting an adaptor and I'm not sure you can.

???

Canon Macrolite Adapter 67.  $32, in stock at B&H, Amazon, etc. 

7455
Third Party Manufacturers / Re: Canon may be expensive but...
« on: February 03, 2013, 03:22:15 PM »
@ Neutral - Thanks, and of course, that's absolutely true if the blown highlights are due to saturation of wells with photons prior to application of the user-selected amount of gain (but note that some gain is applied even at ISO 100, since the 'base ISO' of most current sensors is actually a bit less than 100).

But highlights can also be blown by less-than-full photon wells being subjected to too much analog gain as they are read out. That can happen at higher ISO settings (which are often needed for action-stopping shutter speeds or narrower apertures chosen for sufficiently deep DoF at handholding shutter speeds).  In that case, simply reducing the gain (i.e. ISO) by one stop will preserve one stop of highlights, and that's what HTP does at ISO 400, for example.  No change to aperture or shutter speed, so no change in the amount of light hitting the sensor, but rather, a (clandestine) reduction in the analog gain.

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