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Messages - curby

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Technical Support / Re: Sharpest f stop for a lens?
« on: October 03, 2013, 02:37:09 AM »
The OP asked where lenses tended to be sharpest, and if there's a rule of thumb that generally works.

The whole "how much does sharpness matter" debate is irrelevant, because it's still nice to know about patterns in lens performance even if it's not of practical importance for every shot.  There are geeks, enthusiasts, and engineers-at-heart in this hobby that are interested in the science too!

As others have suggested, I often look at reviews to get an idea of where my lens's weak and strong areas are.  That's never the first thing in my mind as I compose a shot, but sometimes it's useful additional information when you have time to set up a shot and carefully consider lens sweet spots along with other factors. 

For viewing and editing photos, I'd definitely go for a retina MBP if you can afford it (in terms of price, size, weight).  Simply put, the screen matters for your use case.  A LOT.

The most consistently worst part about Apple laptops for me has been the screen.  Glass multitouch trackpads rocketed Apple to the best in the biz, the move to x86 nixed the PPCs that just couldn't keep up, but until the rMBP the screens have been horrible.  Sure the review sites would tell you that for TN panels, the gamut, color accuracy, and contrast were decent, but as we know specs aren't the whole picture. TN panels have horrible color saturation shifts at different vertical viewing angles.  The IPS panel of the rMBP fixes that.  Now you have desktop-level resolution, and desktop level color consistency across viewing angles.  Now you have a laptop that you can edit photos on without having everything wash out because you sat up in your seat a few inches.  (And if you fly coach, you can now sit in a cramped seat and look down onto the screen with much better color saturation.)

But as others have said, wait 'til the end of the month, when Apple is expected to announce the next-gen, Haswell-bearing, rMBPs.  That also gives you another month to save up for it!   ;D

I first heard of this from Arthur Morris, and am considering switching as well.  He recommends leaving the camera in AI Servo mode all the time.  I like to hear the AF confirmation beep though, and that never happens on my old Rebel during AI Servo mode.  I know the idea is that it's continually tracking instead of locking focus, but a beep to confirm the initial focus acquisition would still be useful (to me).  Can newer bodies beep on initial focus during AI Servo mode, or do they still only ever beep during 1-Shot AF?

P.S. Does the back focus option stay set during Green Box mode?  I imagine you'd often want to go full auto when handing your camera to a total newbie anyway.

EOS Bodies - For Stills / Re: Using Custom Dial Settings
« on: August 08, 2013, 12:43:22 AM »
Thanks for all the ideas, folks.  I guess I'll have to play around with it to see what works.  Unfortunately, I'm just an amateur with wide interests from birding to landscapes to food and product photography ... so it might be hard to land on a single useful preset. 

EOS Bodies - For Stills / Using Custom Dial Settings
« on: August 06, 2013, 10:29:13 PM »
Hi folks, looks like the 70D is going to be my upgrade from my 400D.  I need better AF than the 6D, and lower prices than the 5DIII.  Something I've never used though is custom modes (C1, C2, etc.) on the mode dial.  I get how setting different drive/metering/etc. modes may be useful if you're using one body to quickly switch between multiple types of shots, but of what use is the single C mode of the 70D?  I guess you set up your M/Av/Tv/P mode to be a pseudo-custom mode, then use the C mode for something else and switch between those?  If so, don't the five clicks from C to P (worst case example) reduce the usefulness of a custom mode as a shortcut or time saver?

How many of you with newer bodies use your C modes?  How are they set up, and what shooting situations do you use them in?  Do you use them in conjunction with the "normal" M/Av/Tv/P modes? 

In a nutshell, I'm trying to understand how this feature could help, especially when there's only one.  Thanks!

To reiterate, the goal is smaller final images anyway: I wonder what thkn's images would look like if they were all resized to SRAW size.  Would the resizing lessen the perceived chroma noise of the full RAW images?  From those limited tests, I'm not seeing a lot of benefit to the full RAW (such as greater detail), and the reduced chroma noise of the SRAW images seems like a pretty compelling benefit.  Of course, that goes against what most people here are saying: namely, that shooting SRAW does NOT offer such advantages. 

Thanks for the tests!  I might have to do my own testing when I upgrade my body to something that can do smaller RAWs. 

IF Canon did it right you get free image stacking (4 images) which should result in less noise and better color reproduction

^ This is the crux of my question: if I don't need the full sensor resolution anyway, maybe doing (some of) the downsizing ahead of time results in a better final image.  It all depends on the specifics of how RAW and sRAW actually map sensor sites to the file.

Relatedly, does anyone know whether Canon's RAW format stores post-interpolation RGB pixels, or does it separately store the red, green and blue data as pre-interpolation discrete readouts?  If the latter, whatever smarts could have been applied to the sRAW should still be applicable to the full sized RAW image.

EOS Bodies - For Stills / Do smaller RAW formats give lower noise?
« on: July 09, 2013, 01:17:17 AM »
tl;dr version: I'm really interested in low noise during low-light/high-ISO shots, and am wondering if shooting in smaller RAW formats could help in that effort.

I'm betting it doesn't work, but what does shooting in smaller RAW sizes (e.g. M-RAW, S-RAW) actually do in terms of mapping sensor sites to the final image, and can it combine sensor site outputs to increase apparent light sensitivity without boosting ISO?  And if not, why not?

Example: take a 20 megapixel sensor, intelligently combine the readings of each block of 2x2 red, green, and blue neighboring sensor sites, and spit out a 5 megapixel image.  If that's done closer to the sensor, before the interpolation of subsensor sites into RGB pixels, might it result in a better (e.g. lower noise) result?  The idea would be to discard the outputs of aberrant sensor sites before they could muddy the interpolation algorithm and "dirty" more final pixels.  I wonder if that would be better than taking a full resolution image, applying noise reduction post-processing tools, and spitting out a 5 megapixel image at the end of the workflow.

Any thoughts?  Anyone actually know how sensor sites are mapped onto S-RAW and M-RAW image pixels?  Thanks!

Lenses / Re: Photozone spanks the 24-70 F4 USM L IS
« on: March 06, 2013, 08:32:10 PM »
I agree with the above, with two caveats/clarifications:

1) Apple has more than its share of rabid fans, but it's not just the media that has insanely high expectations of them; their users howl about every real and perceived fault.  I'm a long-time Mac user, and have caused many friends and family to purchase them too, but boy do I hate their mice, cloud services, and every laptop screen they've ever put out before the retina.

2) The market will bear what the market will bear.  Going back to Apple, everyone said the iPad mini was overpriced, but they still couldn't keep them in stock.  Lowering the initial price would have just been a bad business decision that would have left money on the table.  $30 for a Lightning cable is a lot, but now there are cheaper options available.  $1500 for this lens is a lot, and will either plummet in price if the naysayers here are right, or will stay high if it does turn out to be as popular as Canon bet on.

Ultimately, I hope the performance problems Photozone found are limited in nature, as supported by other reviews not mentioning the problem and other users who can't reproduce the problem.  If not, then Canon truly made a misstep not only in the pricing, but in releasing a lens that simultaneously offers high-magnification performance as a headlining feature yet suffers from critical issues when using that feature. 

Lenses / Re: Photozone spanks the 24-70 F4 USM L IS
« on: March 05, 2013, 11:19:42 AM »
See his Tamron 24-70 IS ... review

Do you have a link?  This page doesn't seem to have many details.  Thanks!

Lenses / Re: Photozone spanks the 24-70 F4 USM L IS
« on: March 05, 2013, 01:13:16 AM »
It's a deal breaker for me. I have zero interest in a lens with focus shift problems.

Sure, but does the lens have focus shift problems?  A refresher:

the focus shift issue which I haven't seen mentioned anywhere else thus far

I wonder why that hasn't been all over the internet already! Maybe sample variation did play a role here?  ???

Here are some reviews and hands-on previews, all of which fail to mention any sort of fous shift issue with the lens.  Is everyone else's testing methods so non-rigorous that they miss this problem, is it in fact not a problem during real life use of the lens, or did photozone get a bad lens? * **

Lenses / Re: Photozone spanks the 24-70 F4 USM L IS
« on: March 04, 2013, 07:15:22 PM »
OK, I'm getting really confused now.  Here are some reviews and hands-on previews, all of which fail to mention any sort of fous shift issue with the lens.  Is everyone else's testing methods so non-rigorous that they miss this problem, is it in fact not a problem during real life use of the lens, or did photozone get a bad lens? * **

* Roger mentions that his writeup specifically did not deal with focusing issues, but I imagine he would have mentioned something if he discovered a glaring problem.

**  :-X

Lenses / Re: Photozone spanks the 24-70 F4 USM L IS
« on: March 04, 2013, 06:26:13 PM »
So does anyone remember the wide open LoCA shot for the Photozone review of the Tamron?  It shows the same softness that plagues the Canon:

Why was that not called out as a fault during the Tamron review?  I think I'm missing something here because it seems like a very similar problem, but it wasn't discussed as such in the Tamron review.

On the other hand, I cannot imagine a situation where I set the aperture AFTER focusing, so I don't see a big issue here.

Oh, is that all it was?  I thought that when you stop down to say f/8, the camera is still doing focusing with the lens wide open.  It's not until you click that the lens stops down to f/8, effectively changing the aperture after focusing.  What's really going on here?

people seem to just enjoy hating the 24-70 IS.

That just makes it the perfect kit lens for the well-hated 6D.  ;D

Lenses / Re: Photozone spanks the 24-70 F4 USM L IS
« on: March 04, 2013, 05:51:50 PM »
Interesting results, to be sure.  This lens, along with the Tamron 24-70/2.8 VC, are frontrunners for replacing my 17-55/2.8 IS if I end up going full frame later on this year.  Seems like I'd be trading focus shifting and smaller aperture for portability (smaller lens, and I probably wouldn't need a dedicated macro). 

Odd that the review didn't really mention macro performance too much, and none of the sample shots show a close focus situation.  I guess the LoCA section is meant to cover that.

RLPhoto: Macro means a large magnification, and for a non-dedicated Macro lens this qualifies handily.  The "all-in-one" nature of this lens means I can carry a smaller, lighter kit, and that's precisely why it's even in the running besides the otherwise superior Tamron. 

In the end, the focus shift issues and price are two sides of the same problem.  With great resolution, amazing versatility, compact size, and durable construction, I wouldn't mind paying the asking price if it focused more reliably at macro ranges.  On the other hand, I could allow for such quirks if they asked less.  The combination of the two makes it a hard pill to swallow though.

Pricewatch Deals / Re: Deals: Canon EOS 5D Mark III & Canon EOS 6D
« on: March 04, 2013, 05:23:31 PM »
I think that's a bit of a loss for everyone.

I prefer the paper specs of the 24-70 f/4 L with near-macro capability, largely due to the near-macro capability.  I'm just a little unsettled by the bad quality reports people have given, but those reports don't seem consistent either.  Hmm.

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