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Messages - ecka

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211
EOS-M / Re: Am I missing something in the math/conversion here?
« on: August 05, 2013, 11:55:30 AM »
I'm getting an M. Mostly this will be my Parks (WDW) travel setup where the 5D3 is too bulky/heavy.

I'm thinking for Animal Kingdom in bringing the M with the Tamron 70-200 + 1.4 TC. I get 448mm @ f/4. Is that right?
The "M" is APS C, so you will see a angle of view 1.6 X that of a 200mm lens, or 320mm.
Have you tried one with the Tamron? I would not expect it to work well with a Tamron lens, it may be extremely slow to focus.  Most third party lenses do not play well with Canon's live view.  There is no phase detect with a EOS M, so try first or make sure you can return it.
With a huge lens, the body size makes only a slight difference, and balance may be poor.  You might be far better off with a SL1 and the ability to use phase detect AF if you want a small body.  Tamron Af will work reasonably well with phase detect.
 
Good Luck.

+1
SX50'HS is a nice, small, almost pocketable, cheap super telephoto, but if you want better IQ, then you should avoid TC's on zoom lenses as well. Otherwise, you won't get a much better result than a super-zoom P&S camera.

212
Lenses / Re: Sigma 24-70 f/2 OS HSM Coming? [CR1]
« on: August 01, 2013, 10:01:08 AM »
Canonwatch has what is purported to be a leaked image, would seem this beast is getting a bit less mythical.

http://www.canonwatch.com/rumor-first-picture-of-sigma-24-70mm-f2-lens-leaked/

Looks fake to me.
120-300/2.8 and 18-35/1.8 photoshopped hybrid.

213
PowerShot / Re: What's Coming August 21, 2013? [CR2]
« on: July 31, 2013, 12:30:47 PM »
Canon will be showing off their new headquarters, that's all :).

214
Actually, it would (kind of) make sense if every next FL had around 2x smaller FoV, like:
12mm<17mm<24mm<35mm<50mm<70mm<100mm<135mm<200mm<300mm<400mm...
or
10mm<14mm<20mm<28mm<40mm<60mm<85mm<120mm<180mm<250mm<350mm<500mm...

If you compare fast Canon L primes
24/14~1.71 >> 1.71*1.71~2.92x
35/24~1.46 >> 1.46*1.46~2.13x
50/35~1.43 >> 1.43*1.43~2.04x
85/50=1.7 >> 1.7*1.7=2.89x
135/85~1.59 >> 1.59*1.59~2.53x
200/135~1.48 >> 1.48*1.48~2.19x
then you'll see that they are not evenly spaced. The FoV difference varies from around 2x to almost 3x.

215
Lenses / Re: Sigma 24-70 f/2 OS HSM Coming? [CR1]
« on: July 30, 2013, 03:27:41 AM »
Sigma 24-70 f/2 OS HSM - great! It could be THE lens for videographers. Now let's think about it realistically:
very BIG, very HEAVY, not weather-sealed (most likely);
much more expensive than 24-70/2.8L'II, could be $3k+ (just look at the 120-300/2.8 ).

216
Software & Accessories / Re: Importing images method...???
« on: July 30, 2013, 12:12:29 AM »
Copy images, never move.  Make sure your copy is good, and then make sure you have a backup of that location.  Only then, format the card to make it squeaky clean.

+1
I load many cards as copy and paste after a trip and keep the originals until I am done with all the PP and copy / backup the final images.  Only then will I delete or reformat the card.

+1
+NEVER touch the contacts on SD cards, because static electricity may corrupt the data.

217
Software & Accessories / Re: Importing images method...???
« on: July 29, 2013, 03:46:38 PM »
Transcend USB 3.0 Super Speed Multi-Card Reader (SD/SDHC/SDXC/MS/CF)
TS-RDF8K

Importing images directly from camera using the USB cable has a higher chance to corrupt your images, specially if it is connected through a hub along with other USB devices. USB 3.0 is much faster.

218
I'm using Sigma 150/2.8HSM since 2009. It is my favorite lens. Can't say anything bad about it. For the price/size/weight in 150-180mm range f/2.8 Macro it has no competition. The new one may be a little bit better +stabilized, but it is bigger, heavier and more expensive as well. It is an excellent outdoor portrait and tele lens too. The bokeh is very nice.

219
6D Sample Images / Re: Anything shot with a 6D
« on: July 24, 2013, 12:10:24 PM »
Thanks, guys. Actually, it was 1/200sec, ISO 100, f/5.6, using shorty-40 at MFD.
I have more :)


IMG_1105 by ecka84, on Flickr


IMG_1062 by ecka84, on Flickr


IMG_1087 by ecka84, on Flickr

220
6D Sample Images / Re: Anything shot with a 6D
« on: July 24, 2013, 02:23:44 AM »

IMG_1083 by ecka84, on Flickr

221
"Whether or not regions outside the focal plane appear sharp...that's DoF" - That applies to your eyes, not the original image.

Yes, it still applies to the original image. Tell me...how do you calculate your (incorrect) concept of the "DoF" of 'the original image'.  I'd like to see the math behind that, if you could share it.  Also, what do you even call THAT THING - because it's not the DoF, by definition.

Regardless, while a tree falling in the forest with no one around to hear it does, in fact, make a sound, a photograph without someone to look at it is a completely meaningless collection of 0's and 1's or an equally meaningless collection of developed silver halide grains in an emulsion. The moment someone views it, all of my points about CoC apply...and that, for all purposes relevant to photographs, is the real end of the discussion.

Imagine that you are a cyborg and you see the world through cameras instead of eyes. One camera has 8mp APSC sensor from 20D and another one has 21mp FF sensor from 5D2 (yes, it's weird, you must be made in China, or something). Both with 40mm f/2.8 lenses. You see everything in clearest details up to a single pixel, all of them, all the time. FF camera has 60% wider FoV, but with both lenses focused at the same distance you would see that they both produce the same DoF.
This is a very simplified concept (no need to tell me that), because I don't want to waste any more time on this, but it is real and correct. That's how your camera sees it and renders the DoF. The question is not "How do my eyes deal with DoF?". It is "How the camera does it?". It may not be useful for thumbnails and snapshots, but there is a need for it in photography with extremely shallow DoF and a lot of cropping, like macro (where you can't bring it back if it's oof).

222
I suggest you to read all my posts in this thread, it might help to understand my position (if you didn't already).
Z-axis resolution? Where did that come from? The only thing that sensor gathers is the light to determine a color for each pixel. Everything else is just information manipulation. If you really don't understand how to define "the sharpest area", then you should study the principles of CDAF, it's all there.

I did read them, and it appears that you don't really understand what DoF is, or at least such understanding isn't coming across in your posts.  For example, "...CoC is about perception. DoF is not, it is about information..., and several iterations thereof.  That seems to sum up your argument, but that statement is fundamentally wrong. You cannot determine DoF without a CoC value, either arbitrarily chosen or empirically determined. DoF is based on CoC and other factors, so if you believe that you can determine DoF without CoC, you don't understand what DoF means.

As for 'the sharpest area', that's the focal plane, the plane in space at which the lens is focused. It's a plane, with effectively no depth (although practically, it has some - just as real lenses aren't the infinitely thin lenses we pretend they are for optical calculations).  Everything in front and behind that plane is less sharp, progressively more so at increasing distance along the optical axis. Whether or not regions outside the focal plane appear sharp...that's DoF, and it is affected by several factors, including CoC.

I understand the physics and if I don't quote books and articles, or post links for others to go read something, it doesn't mean that I don't understand a thing. I'm using my own head, because it is science, not a religion. Science provides tools, but you cannot use the same one for everything.
Does the CoC theory work for upscaling images? - No.
Are imaging sensors rendering DoF in a way you described - "a plane, with effectively no depth" where "everything in front and behind that plane is less sharp"? - No.
"Whether or not regions outside the focal plane appear sharp...that's DoF" - That applies to your eyes, not the original image. Think about it. It's like photographing a photograph.
End of the discussion ;).

223
I'm not asking about the illusion of sharpness, I'm asking about the information that camera can capture in the sharpest area.

Of course that's related to pixel size (but less spatial information than the pixel size suggests, due to AA filter effects, lens aberrations, etc.).

The question is, how do you define the 'sharpest area'?

Not all sensors have AA filters, not all are based on Bayer filter technology.
The sharpest area carries the highest amount of information about reality, compared to the rest of the image.

True, but your definition is something of a tautology.  In terms of the real world being captured by the image sensor as sampled by the lens, how do you define 'sharpest area'?  Specifically, does that area have 'depth' relative to the sensor?  Pixel size represents the least quantifiable unit of XY resolution. What about Z-axis resolution?  After all, the latter is what this thread is about...

I suggest you to read all my posts in this thread, it might help to understand my position (if you didn't already).
Z-axis resolution? Where did that come from? The only thing that sensor gathers is the light to determine a color for each pixel. Everything else is just information manipulation. If you really don't understand how to define "the sharpest area", then you should study the principles of CDAF, it's all there.

224
I'm not asking about the illusion of sharpness, I'm asking about the information that camera can capture in the sharpest area.

Of course that's related to pixel size (but less spatial information than the pixel size suggests, due to AA filter effects, lens aberrations, etc.).

The question is, how do you define the 'sharpest area'?

Not all sensors have AA filters, not all are based on Bayer filter technology.
The sharpest area carries the highest amount of information about reality, compared to the rest of the image.

225
Metaphorically speaking, it appears that many people are trapped within the circle of confusion, when it comes to discussions of DoF.

1. The formulas used to calculate DoF all contain CoC as a variable.
2. CoC is dependent on the observer's visual acuity, viewing distance, and output size.

Therefore,

3. DoF is dependent on the observer's visual acuity, viewing distance, and output size.

It's really that simple.

As for Ecka's argument about one pixel, the typically assumed values for CoC, and the practical range of CoC values for other print sizes and viewing distances, are much larger than a single pixel, so spatial quantization is not an issue.

I'm not asking about the illusion of sharpness, I'm asking about the information that camera can capture in the sharpest area.

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