Blackmagic Forum

The BMCC has a crop of 2.3X at 2.5K making a 300mm act like a 690mm

The BMPC has a crop of 1.6X at 4K making a 300mm act like a 480mm

Now my question is which has more "zoom" after cropping in to 1920x1080 in post? Math isn't my forte... Which would you take into the field to film wildlife?

I just got my BMCC a few weeks ago. Its amazing the reach the sensors size gives you on long lenses. I have a canon 300mm 2.8 and a 1.4X which gives me a image almost equal to 1000mm f4 on a full frame sensor... That doesn't suck. Its also doing well for me in low light. Im coming from a DSLRs and I shot on 5d2's and I got a 7D for "reach" for wildlife. The BMCC is better then the 7D in my opinion for low light. Especially when shooting raw and bringing it back in post. Haven't been on any trips yet but this is from behind my house. Full size grab from the raw footage. Edited in Aperture.

Thanks

William Altman wrote:The BMCC has a crop of 2.3X at 2.5K making a 300mm act like a 690mm

The BMPC has a crop of 1.6X at 4K making a 300mm act like a 480mm

Now my question is which has more "zoom" after cropping in to 1920x1080 in post? Math isn't my forte... Which would you take into the field to film wildlife?

I just got my BMCC a few weeks ago. Its amazing the reach the sensors size gives you on long lenses. I have a canon 300mm 2.8 and a 1.4X which gives me a image almost equal to 1000mm f4 on a full frame sensor... That doesn't suck. Its also doing well for me in low light. Im coming from a DSLRs and I shot on 5d2's and I got a 7D for "reach" for wildlife. The BMCC is better then the 7D in my opinion for low light. Especially when shooting raw and bringing it back in post. Haven't been on any trips yet but this is from behind my house. Full size grab from the raw footage. Edited in Aperture.

Thanks

A 1080p crop from "4k" on a 1.6 crop sensor would make a 300mm act like a 960mm as the 1080 is half the width of "4k" (1080 * 2 = 2160) (1920 * 2 = 3840)

and a 1080p crop from "2.5k" on a 2.3 crop sensor would make a 300mm act like an 862.5mm (1080 * 1.25 = 1350) (1920 * 1.25 = 2400)

m * C * c = M

m = lens (mm)
C = sensor crop factor in comparison to Full Frame
c = width of resolution shot / width of resolution cropped to
M = new lens (mm) equivalent

C = 36mm (width of full frame sensor) / width of active sensor area

BMPC = 36/21.12 ~ 1.7
BMCC = 36/15.81 ~ 2.3

so really a 300mm with a 1080p crop from the BMPC at 4K would be about 1020mm

TZuck wrote:m * C * c = M

m = lens (mm)
C = sensor crop factor in comparison to Full Frame
c = width of resolution shot / width of resolution cropped to
M = new lens (mm) equivalent

C = 36mm (width of full frame sensor) / width of active sensor area

BMPC = 36/21.12 ~ 1.7
BMCC = 36/15.81 ~ 2.3

so really a 300mm with a 1080p crop from the BMPC at 4K would be about 1020mm

Thanks for this. Hope to have some wildlife to post before to long... Got almost two straight months in NWT and Alaska early fall!