10-19-2013, 09:54 PM
Time for some updates for those DX × 1.5 = FX fairytales of Klaus and Brightcolours. Sorry guys, I tried to see what happens and what I saw was not confirming your statements. In terms of same DOF - okay. Everything else, especially the blah about how many light a sensor needs - you're wrong.
![[Image: Gal%20comparison%2001%2032DX-50FX-X3.jpg]](http://sojujo.smugmug.com/Testshots/Sigma-183518/i-XkCP3rG/0/X3/Gal%20comparison%2001%2032DX-50FX-X3.jpg)
If you'de be right there would be no visible line between those shots: top one is 50mm FX, bottom is 32mm DX. Same DOF, yes, same perspective, never! Same shutter time (DX f/1.8, FX f2.8)? Nope.
![[Image: Gal%2050_32mm-X3.jpg]](http://sojujo.smugmug.com/Testshots/Sigma-183518/i-fFwQSH4/0/X3/Gal%2050_32mm-X3.jpg)
Those two shots also should be identical, those were done with 50 and 32 again at f/1.8 (DX) and f/2.8 (FX). The whole perspective is different. FX was 7360 pixels width and DX was 4800 which is clearly no 1.5× factor (Otherwise FX would be defined as 7200 pixels).
1st wrong assumption: f/1.8 at DX = f/2.8 at FX: No. Same shutter speed, same ISO and f/2.8 was darker - everything else would be strange.
2nd wrong assumption 18mm DX = 27mm FX or 32.5mm DX = 50mm DX: No, perspective was different - in all shots the proportions were different, the bokeh clearly was different.
This "crop 1.5" is a fairytale in more than one aspect, but that's not the point. It's simply, there's no such lens for DX at all. Telling "it's only 27-52.5/2.8 on DX" is plain crap. Nobody needs to update to FX for a fast wide-angle now. But there's one serious downside for this lens. It is sharp, the AF is working well, but it definitely needs state of the art AF. Here's the camera the limit. On a D7000 I had several problems. Looking to Canon EOS 70D - excellent reliability, almost everytime. Nikon D7000: lucky you if you choose the right AF point. D7100 is a bit better. It's just, those huge AF indicator rectangles in finder are too big to nail sharpness precisely. So, please consider some will to improve your focussing technique and some time to adapt. After that it's incredible.
Oh, almost forgot: It is producing some more flares than I was desiring when pointing into direct sunlight. But then, I'm used to worse flares from 14-24/2.8 FX which is over 2 times more expensive, so what?
If you'de be right there would be no visible line between those shots: top one is 50mm FX, bottom is 32mm DX. Same DOF, yes, same perspective, never! Same shutter time (DX f/1.8, FX f2.8)? Nope.
Those two shots also should be identical, those were done with 50 and 32 again at f/1.8 (DX) and f/2.8 (FX). The whole perspective is different. FX was 7360 pixels width and DX was 4800 which is clearly no 1.5× factor (Otherwise FX would be defined as 7200 pixels).
1st wrong assumption: f/1.8 at DX = f/2.8 at FX: No. Same shutter speed, same ISO and f/2.8 was darker - everything else would be strange.
2nd wrong assumption 18mm DX = 27mm FX or 32.5mm DX = 50mm DX: No, perspective was different - in all shots the proportions were different, the bokeh clearly was different.
This "crop 1.5" is a fairytale in more than one aspect, but that's not the point. It's simply, there's no such lens for DX at all. Telling "it's only 27-52.5/2.8 on DX" is plain crap. Nobody needs to update to FX for a fast wide-angle now. But there's one serious downside for this lens. It is sharp, the AF is working well, but it definitely needs state of the art AF. Here's the camera the limit. On a D7000 I had several problems. Looking to Canon EOS 70D - excellent reliability, almost everytime. Nikon D7000: lucky you if you choose the right AF point. D7100 is a bit better. It's just, those huge AF indicator rectangles in finder are too big to nail sharpness precisely. So, please consider some will to improve your focussing technique and some time to adapt. After that it's incredible.
Oh, almost forgot: It is producing some more flares than I was desiring when pointing into direct sunlight. But then, I'm used to worse flares from 14-24/2.8 FX which is over 2 times more expensive, so what?