85mm portrait lens
Aug 3, 2019 07:23:52 #
DaveyDitzer wrote:
This offers a case in point. With more than just a single subject head and shoulders portrait, 85 would require stepping back a bit. OTOH a head shot might work better with a 105. In my film days the Nikkor 105 f2.5 was considered the gold standard - tack sharp. However a 75 year old subject might not want tack sharp anymore. You need to decide what portrait formats you want to prepare for then choose the focal length; OR get a good zoom lens
If I read this correctly, all these figures. were “film days” .... 35mm .... ‘FF’ .... so corresponding focal lengths would be 55mm .... 70mm ‘APS-C’.
Aug 3, 2019 10:32:35 #
A 50mm lens on a crop sensor camera will give the perspective of a 75mm lens, but it is still a 50mm lens, you can use a conversion factor of 0.6 to find out how you lens will "look" on your camera. For example if you have a 50mm lens on a crop sensor camera body divide the focal length by 0.6
A 50mm lens on a crop sensor camera will have the approximate perspective of an 85mm lens
50/.6=83.333 and so on
A 50mm lens on a crop sensor camera will have the approximate perspective of an 85mm lens
50/.6=83.333 and so on
Aug 3, 2019 13:21:20 #
tturner wrote:
A 50mm lens on a crop sensor camera will give the perspective of a 75mm lens, but it is still a 50mm lens, you can use a conversion factor of 0.6 to find out how you lens will "look" on your camera. For example if you have a 50mm lens on a crop sensor camera body divide the focal length by 0.6
A 50mm lens on a crop sensor camera will have the approximate perspective of an 85mm lens
50/.6=83.333 and so on
A 50mm lens on a crop sensor camera will have the approximate perspective of an 85mm lens
50/.6=83.333 and so on
How are you arriving at this conversion factor of 0.6 there are different crop sensors?
Aug 3, 2019 13:22:37 #
Aug 3, 2019 13:24:13 #
Aug 3, 2019 13:32:31 #
Aug 3, 2019 13:42:31 #
RichardSM wrote:
You too picked up on this?
Adjusting the crop factor for use as a divisor rather than a multiplier is a bit unusual, as well as yielding a different equivalent focal length ....
Aug 3, 2019 14:04:20 #
The sensor on my camera which has an APSC sensor has a dimension of 23 x 15mm, a 35mm film camera has dimensions of 36 x 24mm if you apply the pythagorean theorem you will find that the APSC sensor has a diagonal dimension of 27mm and the full frame sensor has a diagonal of 43mm.
if you divide 43 into 27 you will get a figure of 0.62 which can be rounded to 0.6
So if you have a film camera lens on a camera with an APSC sensor, divide the focal length by 0.6 and you will arrive at the equivalent focal length for you APSC camera.
Example 50mm divided by 0.6 equals 83.333.
If you want to find the "normal" focal length lens for a given camera simply apply the pythagorean theorem and you will find the exact focal length. Example, a full frame camera has a dimension of 36 x 24mm
36 squared plus 24 squared then find the square root, which is 43mm which can be rounded to 50.
It is not the new math or the heat in Savannah, it is simple geometry, those of you who have grown up in the digital world and do not know how to think for your self would not understand this, those of us who came from the "old" school understand that knowledge is power.
if you divide 43 into 27 you will get a figure of 0.62 which can be rounded to 0.6
So if you have a film camera lens on a camera with an APSC sensor, divide the focal length by 0.6 and you will arrive at the equivalent focal length for you APSC camera.
Example 50mm divided by 0.6 equals 83.333.
If you want to find the "normal" focal length lens for a given camera simply apply the pythagorean theorem and you will find the exact focal length. Example, a full frame camera has a dimension of 36 x 24mm
36 squared plus 24 squared then find the square root, which is 43mm which can be rounded to 50.
It is not the new math or the heat in Savannah, it is simple geometry, those of you who have grown up in the digital world and do not know how to think for your self would not understand this, those of us who came from the "old" school understand that knowledge is power.
Aug 3, 2019 14:31:53 #
I've forgotten how fun it is to meet someone who knows more than everyone, including the camera manufactures themselves. Some recent work of yours has EXIF for a Pentax K10D. I took the liberty of checking the user manual for that model, a 1.5 crop factor. Granted, these factors are nearly always expressed as 'approximate' where 80mm and 83mm are approximately the same, with 1.5x being typically easier math than consulting the Pythagorean theorem and the sensor dimensions to achieve an approximate field of view of a 35mm lens. But, what would everyone else know ...
Aug 3, 2019 14:46:20 #
CHG_CANON wrote:
I've forgotten how fun it is to meet someone who knows more than everyone, including the camera manufactures themselves. Some recent work of yours has EXIF for a Pentax K10D. I took the liberty of checking the user manual for that model, a 1.5 crop factor.
Thank you for proving my point, you can apply it any way you like, and you will get the same result, and yes my camera has a sensor of 23 x 15mm approximately. This is only one method, I have seen portraits taken with almost every focal length available, it does not matter, as long as you are getting the desired result so there is no need to figure out crop factors, just do what works for you.
Aug 3, 2019 14:50:13 #
Aug 3, 2019 15:25:41 #
Leitz
Loc: Solms
tturner wrote:
How do you think the crop factors were calculated in the first place.
By dividing the FX diagonal by the DX diagonal?
Aug 3, 2019 15:32:05 #
Aug 3, 2019 15:42:08 #
Aug 3, 2019 15:46:11 #
In the mean time, multiple dead and wounded at a Walmart shooting in El Paso Texas, do you think this lens thing really matters?
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