dhessel Posted December 14, 2015 Share Posted December 14, 2015 You are correct if you want to know the new focal length in 35mm/Full Frame equivilant then you multiply the focal length x crop factor x focal reduction. However DPreview and the others are also correct in that a 28mm and booster will yeild the fov of a 20mm lens on a MFT camera. In turn that 20mm will have the fov of a 40mm on a Full Frame camera. mercer and Nikkor 2 Link to comment Share on other sites More sharing options...
Phil A Posted December 14, 2015 Share Posted December 14, 2015 I think this is a bit an issue of opinions as to what is scientifically correct and what is "practically accepted reality".Focal lenght is fixed, it doesn't change depending on the camera. So 28mm is 28mm no matter if 35mm, APS-C or M43 sensor, but the crop of the image circle that is used obviously changes, so you will change the distance to compensate for this. Theory goes on and on but....The practical answer you want:28mm on M43 has the field of view like a 56mm on 35mm/FF. So the Speedbooster uses whatever modification, in your case 0.72, which will give you what a 41mm lens would frame on a FF sensor. 28mm x 2 x 0.72 = 40.32mm EDIT: yeah, what dhessel said mercer 1 Link to comment Share on other sites More sharing options...
Guest Ebrahim Saadawi Posted December 14, 2015 Share Posted December 14, 2015 40mm Ff lens, abd a 20mm m43 lens. Equivalent that is. Link to comment Share on other sites More sharing options...
Cinegain Posted December 14, 2015 Share Posted December 14, 2015 Yup. The 0.71 or 0.72x, whatever really, just makes the 28mm lens itself act as if you'd fit on a 20mm lens on there. Optically.The sensor crop of 2x still applies. So, equivalent to FF, it's still 40mm-like. mercer 1 Link to comment Share on other sites More sharing options...
mercer Posted December 14, 2015 Author Share Posted December 14, 2015 Thanks guys! I keep forgetting the FL/FOV differences. Makes perfect sense now. Link to comment Share on other sites More sharing options...
bunk Posted December 14, 2015 Share Posted December 14, 2015 Add another 1.2 to the equation as you only use part of the sensor when filming in UHD (4592/3840)...So it becomes XXmm x 2 x 0.72 x 1.2 or XXmm x 1.72 Link to comment Share on other sites More sharing options...
mercer Posted December 14, 2015 Author Share Posted December 14, 2015 Add another 1.2 to the equation as you only use part of the sensor when filming in UHD (4592/3840)...So it becomes XXmm x 2 x 0.72 x 1.2 or XXmm x 1.72On the G7, the UHD crop is 2x. So, why would I have to add another 1.2? Link to comment Share on other sites More sharing options...
bunk Posted December 15, 2015 Share Posted December 15, 2015 The crop factor of an MFT sensor is 2. Since the G7 only uses part of the sensor you have to calculated that difference as well.Nevertheless I stand corrected. I was under the impression the G7 didn’t do pixel binning in UHD. Turns out it uses a 4120x2318 crop from the sensor to create UHD.4592/4120=1,1145 so that’s an extra 1.1 to add to the equation. So it becomes 1,58 instead of 1,44 (or the 1.72 as I suggested).http://www.cameralabs.com/reviews/Panasonic_Lumix_G7/ just after 3/4 of the page is a nice picture that shows the use of the sensor in UHD. Link to comment Share on other sites More sharing options...
M Carter Posted December 15, 2015 Share Posted December 15, 2015 The crop factor of an MFT sensor is 2. Since the G7 only uses part of the sensor you have to calculated that difference as well.Nevertheless I stand corrected. I was under the impression the G7 didn’t do pixel binning in UHD. Turns out it uses a 4120x2318 crop from the sensor to create UHD.4592/4120=1,1145 so that’s an extra 1.1 to add to the equation. So it becomes 1,58 instead of 1,44 (or the 1.72 as I suggested).http://www.cameralabs.com/reviews/Panasonic_Lumix_G7/ just after 3/4 of the page is a nice picture that shows the use of the sensor in UHD.Beyond all the stabs at science - stick it on your camera and run some tests or shoot for a couple hours. Your brain should file it under the proper category and on a gig you'll reach for it as needed. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now