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next PZ lens test report: Sigma 50-100mm f/1.8 DC HSM ART
#11
Quote:   Errrr.....I don't know these!.......like...... how about them.....  pray tell?
The sensors used by Nikon (and others) don't always have the same size, and more often than not are not exactly 1.5x crop.

Take the Nikons D40/50/60/70, for example, had a 23.7mm sensor width, so 1.519x crop factor. This is the biggest size by the way, so it should really be called 1.52x crop.

The D500 has a 23.5mm sensor width, so 1.532x crop factor. The Nikon D3200's sensor has 23.2mm width, 1.552x crop. The D3100, with 23.1mm sensor width, 1.558x crop.

 

My EOS M has a sensor width of 22.3mm, which makes it 1.614x crop. My EOS 6D has a 35.8mm sensor width, making it a 1.0056x crop.

#12
So do we have to calculate strict equivalence for each and every of those formats before we can go shooting - lest we end up with a forbidden equivalent unit? Big Grin

#13
Quote:So do we have to calculate strict equivalence for each and every of those formats before we can go shooting - lest we end up with a forbidden equivalent unit? Big Grin
Yours has a crop factor (compared to 135 format) of 1.290x. Now you know why everything always turned out wider than you anticipated!

 

On a more serious note, the Sigma Quattro H has a crop factor of 1.353x, yet most of the times just gets called "1.3x crop" or "APS-H like Canon's 1D series". In this case, it is handy to know that the difference can be noticable.

#14
Why should a APS-C lens be weaker on an APS-C sensor, dave? The center remains the same and as Klaus asked " Do you really need tack sharp corners at f/1.8?" resolution of 7D MkII and D500 are just the same, so the real question is "have you ever missed a high quality fast standard zoom in that range of FL?" and the next question "...and are you willing to carry it's weight around?"

 

Like with the 18-35/1.8 there is nothing to compete with - as fast and as zoomy, that is. After Sigma's fantastic 50-150/2.8 APO, there's not much choice for fast short tele zooms. There are fixed FLs better than those two zooms - but also no lightweights. To me it appears Sigma is the only manufacturer really caring about APS-C although it's an illusion to get cheap, light and sharp APS-C lenses. They make it like more for their own APS-C/APS-H cameras. And those are more demanding than other products.

 

Klaus mentioned also a fast AF - so you have a nice fast indoor sport zoom, even concerts or theater lens. In all situations when I have the choice to loose the shot because I cannot change lenses fast enough, this thing would have relaxed my stress. When I look back I remember a lot of situations when such a lens would have been the solution. Together with a second body and the 18-35.

 

In low light situations nobody will miss cover performance - you even can't focus in the corners with most APS-C DSLRs and the noise will be killing more resolution than the lens does.

#15
Quote:The sensors used by Nikon (and others) don't always have the same size, and more often than not are not exactly 1.5x crop.

Take the Nikons D40/50/60/70, for example, had a 23.7mm sensor width, so 1.519x crop factor. This is the biggest size by the way, so it should really be called 1.52x crop.

The D500 has a 23.5mm sensor width, so 1.532x crop factor. The Nikon D3200's sensor has 23.2mm width, 1.552x crop. The D3100, with 23.1mm sensor width, 1.558x crop.

 

My EOS M has a sensor width of 22.3mm, which makes it 1.614x crop. My EOS 6D has a 35.8mm sensor width, making it a 1.0056x crop.
 

Don't forget the height BC!

 

 

 So the D40 has a 23.7mm sensor width but with a 15.5mm height.  = 367.35 mm2

 

The D500 has a 23.5mm sensor width but with a 15.7mm height      = 368.95mm2   that's an increase of 1.6 mm2

 

How that fits in with the multiplication factor i don't know.  Perhaps you could enlighten us here?

 

  The Canon 80D has a 22 X 15mm size  = 330 mm2........  38.95mm<span style="font-size:10px;">2<span style="font-size:14px;">......less!</span></span>

 

  The Nikon D500 sensor is therefore  1.118 X larger than the Canon D80 APSc sensor!

 

 Not far off the difference between MF and FF............... <_<

 

 

  I know you like that one BC..!!!   .......... :lol:  :lol:  B)  Big Grin  Tongue  Wink  Rolleyes  Huh

 

  (The biggest Nikon DX sensors are the D3000/D20/D300 in terms of surface area)

Dave's clichés
#16
I suggest you guys meet and count the pixels with a magnifier. You simply can't be too careful with equivalent areas...

#17
Quote:Don't forget the height BC!

 

 

 So the D40 has a 23.7mm sensor width but with a 15.5mm height.  = 367.35 mm2

 

The D500 has a 23.5mm sensor width but with a 15.7mm height      = 368.95mm2   that's an increase of 1.6 mm2

 

How that fits in with the multiplication factor i don't know.  Perhaps you could enlighten us here?

 

  The Canon 80D has a 22 X 15mm size  = 330 mm2........  38.95mm<span style="font-size:10px;">2<span style="font-size:14px;">......less!</span></span>

 

  The Nikon D500 sensor is therefore  1.118 X larger than the Canon D80 APSc sensor!

 

 Not far off the difference between MF and FF............... <_<

 

 

  I know you like that one BC..!!!   .......... :lol:  :lol:  B)  Big Grin  Tongue  Wink  Rolleyes  Huh

 

  (The biggest Nikon DX sensors are the D3000/D20/D300 in terms of surface area)
Dave, the crop factor can be calculated just from the width. Or just from the height. Or just from the diagonal. As the sensors all have a 3x2 aspect ratio. The weird 10mp CCD from the D200 and consorts oddly enough is not a true 3x2 sensor. 

#18
Ok thanks BC, I would use the diagonal as it takes into account both sensor dimensions!

Dave's clichés
  


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