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Mirrorless Z
Z6/Z6ii/Z6iii
Focus shifting (landscape)
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<blockquote data-quote="Paliswe" data-source="post: 804891" data-attributes="member: 48977"><p>I have tried to read all the experiments you have described here, but since I'm not native english speaker I might have missed some details.</p><p>I will however described my experiences with focus shifting. For me the number of pictures I have to take from "before" the subject to "after" is not dependent on the camera but on the lens.</p><p>How big is a focus step? I have five lenses with slightly different focal lengths (and different apertures) that were mounted on my Z6. I have laid out nine rubber cubes with 10 cm intervals (0-80 cm) on the floor and for a number of different focal lengths the camera will take 10 pictures with an offset of 2 steps for each picture, according to the scale found in the camera's menu. The camera thus sends out 20 steps to the lens for each series. On the last image in each measurement series, I note which cube that is in focus.</p><p>To get the same size of the cubes at different focal lengths, the camera is moved out.</p><p></p><p>The lenses I have used are</p><p>24-70 f/4</p><p>24-200 f4-6.3</p><p>70-200 f/2.8</p><p>105mm f/2.8 MC</p><p>60mm f/2.8 Micro F-mount, mounted on an FTZ adapter.</p><p></p><p>With three zoom lenses and two primes, I can get a total of 13 measurement series, two measurement series each for 24mm and 200mm and three measurement series each for 60mm, 70mm and 105mm.</p><p></p><p>The distance for the five measurement series was calculated by setting the smallest focal length, 24 mm, to 1 and the other focal lengths were calculated in relation to this. The shortest focus distance for the two 24-mm lenses is approx. 0.5 m. Then the distance for 60mm == 1.25m, 70mm == 1.46, 105mm == 2.19m, and 200mm == 4.15m. Then the cubes will be the same size on all images. The camera was placed on a Manfrotto Pixi.</p><p>Tape on the floor marked where the camera would be placed for the different focal lengths. The camera was placed so that the sensor itself ended up directly above the pieces of tape.</p><p></p><p>Results</p><p>The last image in a focus series shows which cube the lens' focus ends up on. It varied between the second and eighth cube, ie the focus shifted between 20 and 80 cm.</p><p>For 24-70 and 24-200 with focal length up to 70mm it was 5-6 cubes, for 24-200 at 105 and 200 the displacement was 8 cubes</p><p>For the other lenses, 60mm Makro F-mount, 105mm MC Z and 70-200, the displacement was 2-3 cubes.</p><p>The attached pictures shows the last ones for 24-200mm and 70-200mm at 200mm.</p><p></p><p>What is interesting is that the cheaper 24-200mm lens goes "longer" at 20 microsteps than the 70-200mm does. That means that the more expensive 70-200mm lens have up to 4 times more steps to focus on than the cheaper 24-200. Thus, the 70-200mm lens can focus much more accurately than the 24-200 can within the same focal length.</p><p>I don't know if this has any effect on focusing accuracy in real life when taking a single photo.[ATTACH=full]390529[/ATTACH][ATTACH=full]390530[/ATTACH][ATTACH=full]390531[/ATTACH].</p></blockquote><p></p>
[QUOTE="Paliswe, post: 804891, member: 48977"] I have tried to read all the experiments you have described here, but since I'm not native english speaker I might have missed some details. I will however described my experiences with focus shifting. For me the number of pictures I have to take from "before" the subject to "after" is not dependent on the camera but on the lens. How big is a focus step? I have five lenses with slightly different focal lengths (and different apertures) that were mounted on my Z6. I have laid out nine rubber cubes with 10 cm intervals (0-80 cm) on the floor and for a number of different focal lengths the camera will take 10 pictures with an offset of 2 steps for each picture, according to the scale found in the camera's menu. The camera thus sends out 20 steps to the lens for each series. On the last image in each measurement series, I note which cube that is in focus. To get the same size of the cubes at different focal lengths, the camera is moved out. The lenses I have used are 24-70 f/4 24-200 f4-6.3 70-200 f/2.8 105mm f/2.8 MC 60mm f/2.8 Micro F-mount, mounted on an FTZ adapter. With three zoom lenses and two primes, I can get a total of 13 measurement series, two measurement series each for 24mm and 200mm and three measurement series each for 60mm, 70mm and 105mm. The distance for the five measurement series was calculated by setting the smallest focal length, 24 mm, to 1 and the other focal lengths were calculated in relation to this. The shortest focus distance for the two 24-mm lenses is approx. 0.5 m. Then the distance for 60mm == 1.25m, 70mm == 1.46, 105mm == 2.19m, and 200mm == 4.15m. Then the cubes will be the same size on all images. The camera was placed on a Manfrotto Pixi. Tape on the floor marked where the camera would be placed for the different focal lengths. The camera was placed so that the sensor itself ended up directly above the pieces of tape. Results The last image in a focus series shows which cube the lens' focus ends up on. It varied between the second and eighth cube, ie the focus shifted between 20 and 80 cm. For 24-70 and 24-200 with focal length up to 70mm it was 5-6 cubes, for 24-200 at 105 and 200 the displacement was 8 cubes For the other lenses, 60mm Makro F-mount, 105mm MC Z and 70-200, the displacement was 2-3 cubes. The attached pictures shows the last ones for 24-200mm and 70-200mm at 200mm. What is interesting is that the cheaper 24-200mm lens goes "longer" at 20 microsteps than the 70-200mm does. That means that the more expensive 70-200mm lens have up to 4 times more steps to focus on than the cheaper 24-200. Thus, the 70-200mm lens can focus much more accurately than the 24-200 can within the same focal length. I don't know if this has any effect on focusing accuracy in real life when taking a single photo.[ATTACH type="full" alt="200_24-200_7451.jpg"]390529[/ATTACH][ATTACH type="full" alt="200_70-200_7420.jpg"]390530[/ATTACH][ATTACH type="full" alt="Focus shift result.jpg"]390531[/ATTACH]. [/QUOTE]
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Focus shifting (landscape)
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