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<blockquote data-quote="kurt78" data-source="post: 545730" data-attributes="member: 41901">When using tripod, there is still the movement of the subject. The necesary shutter speed depends on a lot of other factors like mooving subject angular speed, pixel density in sensor.<a href="https://photographylife.com/what-is-reciprocal-rule-in-photography" target="_blank">https://photographylife.com/what-is-reciprocal-rule-in-photography</a>After a little math I discovered for example:Athlete running 20 km/h from side to side at 5m distance without panning using a 50mm lens (or 35 on DX).If I use a D40 (3000 pixels in a 24mm sensor) the blur I get shooting a 1/1000 is about 5 pixels.If I shoot the same with a D7100 (6000 pixels in a 24mm sensor) I get double of pixels blurred.D800 is even whorse, with 11 pixels. That's because of how many pixels are in one cm.D750 is (6000 pixels in a 36mm sensor) with a 50mm is the same as de D7100 with a 35mm.So, I would need to use speeds of 1/8000 to really freeze that athlete or pan the camera following the movement.(I haven't cheked the numbers, it's just a physics point of view)</blockquote>

[QUOTE="kurt78, post: 545730, member: 41901"] When using tripod, there is still the movement of the subject. The necesary shutter speed depends on a lot of other factors like mooving subject angular speed, pixel density in sensor. [url]https://photographylife.com/what-is-reciprocal-rule-in-photography[/url] After a little math I discovered for example: Athlete running 20 km/h from side to side at 5m distance without panning using a 50mm lens (or 35 on DX). If I use a D40 (3000 pixels in a 24mm sensor) the blur I get shooting a 1/1000 is about 5 pixels. If I shoot the same with a D7100 (6000 pixels in a 24mm sensor) I get double of pixels blurred. D800 is even whorse, with 11 pixels. That's because of how many pixels are in one cm. D750 is (6000 pixels in a 36mm sensor) with a 50mm is the same as de D7100 with a 35mm. So, I would need to use speeds of 1/8000 to really freeze that athlete or pan the camera following the movement. (I haven't cheked the numbers, it's just a physics point of view) [/QUOTE]

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