Interceptor121 843 Posted November 30, 2019 Thanks to @Architeuthis I was able to build and test my fisheye zoom rig in the pool on Thursday and it performs amazingly well With a focal length of 8 - 15 mm fisheye this is going to be my primary rig, details of the build and parts needed listed on the blog https://interceptor121.com/2019/11/30/canon-8-15-mm-fisheye-on-the-panasonic-gh5-pool-tests/ Can't upload pictures due to 1 MB limit sorry 1 Share this post Link to post Share on other sites
Tom_Kline 143 Posted November 30, 2019 Glad you found the lens to be sharp. Not sure of the point of the light fall off measurements. The corners of the pool were at a greater distance than the middle, i.e., > 1.5m. Maybe with super-duper long strobe arms so that each strobe would be halfway to each pool end from your position ;->> Share this post Link to post Share on other sites
Interceptor121 843 Posted November 30, 2019 40 minutes ago, Tom_Kline said: Glad you found the lens to be sharp. Not sure of the point of the light fall off measurements. The corners of the pool were at a greater distance than the middle, i.e., > 1.5m. Maybe with super-duper long strobe arms so that each strobe would be halfway to each pool end from your position ;->> If I had two 16" segments I would get 12" inch more each side which is not going to make a huge difference on the sides however may create a black area in the top and bottom of the middle of the frame. The pool wall in the picture is around 8 meters (each tile is 20 cm) so the sides are four meters away therefore it will be - 4 Ev from the strobe the 30 cm that the strobe arm will add will make little difference What would really make a difference is to have strobes that only fall 1 Ev at 120 degrees but that is physically impossible due to inverse square law. Share this post Link to post Share on other sites
Tom_Kline 143 Posted November 30, 2019 The super long arms was an absurd suggestion of course. Possibly slaved strobes placed very 1.5 m to the left and right might have helped. Lighting up a large flat surface with strobes under water is problematic, e.g., walls. BTW I have taken many fisheye shots using just one strobe at the 12 o'clock about a foot above the lens optical axis A-OK. Subject is at point blank range. Seacam strobes with diffusers work rather well. Inon strobes (Z220) with their flat diffusers not so much Share this post Link to post Share on other sites
Interceptor121 843 Posted November 30, 2019 1 hour ago, Tom_Kline said: The super long arms was an absurd suggestion of course. Possibly slaved strobes placed very 1.5 m to the left and right might have helped. Lighting up a large flat surface with strobes under water is problematic, e.g., walls. BTW I have taken many fisheye shots using just one strobe at the 12 o'clock about a foot above the lens optical axis A-OK. Subject is at point blank range. Seacam strobes with diffusers work rather well. Inon strobes (Z220) with their flat diffusers not so much Am sorry Tom I misunderstood you apologies. I do not want to open a whole discussion about strobes but is at a distance of 1 meter and more like I was once you have the power the diffuser is probably what is actually delivering the light. The purpose of that shot was just to prepare for the shots of the divers actually they look lit OK so whatever is going on it works well. I have had and still have a few inon strobes and I think the reason for the poor performance is not the fact that they are flat but that Inon has decided to go for a material that has higher transmission and this in water works not so well. From what I can see diffusers that take 0.8 to 1 stop work better although this seems counterintuitive Share this post Link to post Share on other sites
Tom_Kline 143 Posted November 30, 2019 (edited) No problem ;->> Delete "very" from my earlier post! :-< Yup under water we want to shoot subjects that are about 1 foot to 1 meter away if at all possible. Especially with flash. One needs alternate techniques such as slaved strobes or more ambient light for greater distances IMHO. Pools have their challenges as well. Edited November 30, 2019 by Tom_Kline Share this post Link to post Share on other sites
