Cool, I've been considering the same configurations. How do you find the working distance with the higher diopter options? Raynox specifies the 202 and 505 at 32 and 18.5mm at infinity focus and I've seen 18.5mm also reported for the 150+250 combination. A thin lens model suggests the slab depth available from autofocus would decrease from 5mm with 150+250 to 1mm with the 505. Given sufficient working distance for field subjects to receive light, I was thinking a low cost, manual Arca Swiss screw drive rail might suffice for collecting multiple autofocus subslabs to stack. The thin lens model suggests variation in magnification across the focus range might be too great for this to work well, which I'm not sure of accepting but does have some support from tests I've made at diopters below the 150. (Also, not sure the tripod I have or some of the substrates I work on are sold enough to accurately return to position after such handling, but those are separate problems.)gardenersassistant wrote:I have used the 45-175 a lot (on G3, G5, G80) with Canon 500D (+2 diopters), Raynox 150 (+4.8 diopters), Raynox 250 (+8 diopters), Raynox 150+250 or 250+250 stacked, Raynox MSN-202 (+25 diopters) and (testing only) Raynox MSN-505 (+32 diopters).
Also curious as to your experiences with image quality. Rik has suggested against stacking close up lenses on a few occasions and also mentioned the 202 might degrade with departure from infinity focus, though the latter was in the context of a macro lens focusing to 310mm rather than the 45-175's 900mm. It seems like the 150 and 250 hold up well and I've found a few reports of the 202 improving with closer focus. Presumably there's some interaction with the specific behavior of the autofocus lens's entrance pupil. As a zoom with a fixed length body the 45-175 might be unusual in that regard.
This has been demonstrated by a couple of members here, showing some loss of image quality compared to frames collected without camera motion. The relation between rail feed, video frame shutter speed, and image quality doesn't appear to have been explored much. My rough math suggests depth rates of hundreds of microns to low single digit mm/s appear feasible. In principle, with a slow enough feed and smooth enough motion camera motion blur could be reduced to negligible.dolmadis wrote:Is the alternative of running a 4K stream on a focus rail manually a do-able option?
The approach could also be used with 6k video, given a GH5 or certain more expensive bodies.