Messages

31

Lenses / Re: Canon 35 2.0 IS vs Sigma 35 1.4

« on: February 23, 2013, 10:06:43 AM »

You appear to be citing photozone.de.

No, they are citing me.  I have been critical about Sigma's bokeh before they published their review.

In their images (e.g. of the reed grass), I don't see the "transition zone" issues, especially when compared with the corresponding images in the 35L test which are unarguably less pleasing. It doesn't strike me as a valid reason to disregard the Sigma.

Look at the image with the garbage bin in the foreground; the grass on the right of it. As I said, the Canon has a similar problem but not that bad, IMO.

In the interests of balance, viewers of this video voted the Sigma's bokeh best in a blind comparison.

Battle of the Bokeh - Canon, Nikon Sigma 35mm f/1.4

This is far from the transition zone. Not challenging enough.

Here is a shot with problematic bokeh with the 35L, f/1.4 (my image): It is more or less a torture test. Look for the double lines there. If I wanted to convince you that the 35L had a wonderful bokeh, I would have posted a different image, like this one or this one (both f/1.6). But that would have been either cheating or lack of knowledge because the first one contains foreground blur only (which tends to look good with most well or over corrected lenses), and in the second one, the transition zone is small and does not dominate the image.

So the bottom line is - it takes more than one or two samples to understand what a lens can and cannot do.

32

Lenses / Re: Canon 35 2.0 IS vs Sigma 35 1.4

« on: February 22, 2013, 11:44:45 PM »

The Sigma bokeh (and that of about any other lens) is problematic in the "transition zone". Well blurred background looks good with any lens but when you are close to the focus plane, things change. The 35L has busy bokeh as well; I have seen poor bokeh of Leica lenses, etc., but the Sigma seems to be a champion.

Here is an example from FLICKR (not mine), f/2, 5DII:

http://www.flickr.com/photos/zackhuggins/8483812543/#sizes/l/in/photostream/

33

Lenses / Re: Canon 35 2.0 IS vs Sigma 35 1.4

« on: February 22, 2013, 06:34:20 PM »

My personal opinion - either the 35/2 IS or the 35L. I own the L and I use it often wide open and next to wide open. The 35/2 IS has IS. I would not worry so much about sharpness differences but I am curious to see whether the 35/2 IS can match the "clarity" of the L.

The bokeh of the Sigma can be very problematic. I would not buy it. With fast lenses, bokeh is maybe more important than sharpness.

BTW, we may see a 35LII soon but it will be expensive.

34

EOS Bodies / Re: Canon EOS 7D Mark II Spec List [CR2]

« on: February 20, 2013, 06:38:17 PM »

yes I know what QE is , and ?

You asked about comparisons to others. They are a lot of them there. The newest Canon FF sensors are comparable to the Nikon ones in terms of QE. The current (a bit old already) crop sensors are at 40% or so, so they lag a bit behind. What I expect is to see a new crop sensor with QE around 55% or so. This would be about 1/2 stop better than the current 7D.

I have no idea what to expect about the read noise.

35

EOS Bodies / Re: Canon EOS 7D Mark II Spec List [CR2]

« on: February 20, 2013, 06:31:06 PM »

what is it that I should look after?

The QE figures determine the shot noise per unit area. A sensor with 42% QE, for example will have 1/2 stop better noise performance than one with 30%, at base ISO, at least. (Ratio of 2 is one stop). This is valid for comparisons within the same format.

Then there is data for the read noise, this determines the deep shadow noise.

I know Bob,he is a friend of mine , who has this site.

I read some of his posts elsewhere, he is a smart and funny guy.

36

EOS Bodies / Re: Canon EOS 7D Mark II Spec List [CR2]

« on: February 20, 2013, 06:13:42 PM »

you tell me that this forum  is the best place , but no one have answerered my question,  is this a wish list or is it a reality when it comes to Canons sensors? 24Mp at a APS size and what  is the signal noise ratio with current technology and  the dynamic range compared to others

See this.

37

EOS Bodies / Re: Canon EOS 7D Mark II Spec List [CR2]

« on: February 20, 2013, 06:06:15 PM »

I really have to emphasize this: In no way, ever, can diffraction produce worse results on a higher resolution sensor than a lower resolution sensor. EVER.

That one as well:

"I really have to emphasize this: In no way, ever, can diffraction produce worse results on a higher resolution sensor than a lower resolution sensor. EVER."

Right. I do not know why this obsession with diffraction and not with lens aberrations, for example. The resolution of a system depends on several factors, and if you improve one of them, you improve the final image. At what point you get "diminished returns" is a philosophical question.

38

EOS Bodies / Re: Canon EOS 7D Mark II Spec List [CR2]

« on: February 19, 2013, 09:21:21 PM »

ISO Performance to get close to the 5D3

The rest of the spec list looks pretty darn good, but I'll believe the line about ISO performance when I see RAW files.  But then again, in marketing speak 'close to the 5D3' might mean simply that the native range is 100-12800 (which is 'close to' the 100-25600 native range of the 5DIII and a 1-stop improvement on the 7D spec).  Many times, Canon's statements about ISO performance improvements refer to JPG images or ISO range, not noise levels at a given ISO setting.

+1. To have the same shot noise as the 5D3, the new 7D must have QE of about 125% (if you believe the Sensorgen figures), which is absurd. The only thing the can and should do is to improve the read noise and to bring the QE in line with the recent sensors, Canon included.

39

Lenses / Re: How do yall compose a shot using a fisheye lens?

« on: February 14, 2013, 11:54:59 PM »

I am not sure that those are great examples, but here are a few. I am still learning how to use this lens.

40

EOS Bodies / Re: $1200 7D vs. $1800 5D II?

« on: February 14, 2013, 10:22:24 PM »

The 5D2 with cheap lenses like the 85/1.8, 100/2, 50/1.4 and with the moderate priced 135L will beat the 7D with any lens in the world,  for portrait use. You get cleaner files, better color separation, better (not just stronger) background blur.

You will actually save money with the 5D2.

41

Lenses / Re: Anyone Want an Improved 16-35mm over the much requested 14-24mm?

« on: February 12, 2013, 09:22:55 PM »

I want a 16-35/4 IS (like the Nikon).

42

Lenses / Re: IS or no IS?

« on: February 08, 2013, 09:26:26 AM »

While I'm in favour of IS, I've just read from another poster that IS can affect bokeh

http://www.canonrumors.com/forum/index.php?topic=12818.msg230053#msg230053

while I've put a parallel question in the relevant post but it seemed right to put the question here also - is this correct?

If the IS elements are so decentered at the moment of the shot, to affect the bokeh, this means that without IS, you whole shot would be bokeh only.  Not to mention that you can always turn the IS off.

On the other hand, the IS poses design restrictions, and they might affect the bokeh.

43

Lenses / Re: DXOMark Reviews the Canon EF 35mm f/2 IS

« on: February 07, 2013, 10:45:51 PM »

I'd just get a 24-70 mk II, but f/2.8 would call for even slower shutter speeds.  This lens is really for video, IS isn't usually needed for stills, where subject motion determines the minimum shutter speed.

Very often, the motion you need to stop is that of your shaky hand.

44

Lenses / Re: IS or no IS?

« on: February 07, 2013, 08:53:34 PM »

+1

Don't even think about it. Get the IS version. IS is useful on wider lenses like the 24-105, and indispensable for a 70-200 for the sort of work you have described. You'll have tangibly superior video and a higher percentage of keepers from your stills.
-PW

45

Lenses / Re: What lenses are good enough for the 18mp APS-C sensor? 1000$ limit :)

« on: February 06, 2013, 10:28:24 AM »

So, my question is: Which lenses ARE good enough for the 18mp APS-C sensor?

Lots of answers are: "L mark II"

Define "good enough".
 
Get quality EF-S lenses. They are better suited for your camera. The top EF-S lenses are the 17-55, the 10-22, and the EF-S 60 macro. Some people like the 15-85 as well. When (quality) EF-S lenses cannot fit the bill, get EF lenses, of course. If you find yourself shooting with fast primes wide open too often, then you would need to go FF.