dpoursanidis 1 Posted April 15, 2015 Hi ! A question arrise when i have (or we) to choose/use a new lense that needs a new extension ring (sometimes less that 5-6mm) shorter or longer from what we have (or we can affort to buy....). What is your opinion/experience on this ? Share this post Link to post Share on other sites
TimG 62 Posted April 15, 2015 Hi dpoursanidis It depends! If you are shooting wide-angle, the extension ring (EXR) length is key as it sites the lens in the correct position for the curve of the domeport. So you do need the right length for shooting wide-angle. It's maybe not so crucial if shooting with a flatport and macro. It would the depend on whether the port/EXR combination creates any sort of vignetting which spoils the image you want to create. Chances are a few millimetres here and there will not make too much of a difference. But.... it might! Sorry, maybe this is not terribly helpful but it certainly is my experience. In short: wide-angle/domeports: yes EXR is important. Macro/flatport, maybe not. Share this post Link to post Share on other sites
dpoursanidis 1 Posted April 15, 2015 Hi Tim Example first > Aquatica mini dome + Canon 8-15 + 18453 EXR = Center crop https://copy.com/DxwZqGGdLV8i92L1 Low right crop https://copy.com/yIZvbHuxUjCd0WIE How much "better" can these be with the correct ? Images are from RAW > JPEG. No editing. Natural light shot @ 2m depth. Share this post Link to post Share on other sites
TimG 62 Posted April 16, 2015 Hi dpousaindis Hmmm, not sure what to say! "Better" is a pretty subjective word. Certainly you have some pretty serious blurring going on there and I would have thought you should be able to get it much "better" than that! Sometimes though it depends how much you are prepared to pay to make a difference; and then how much the difference is worth the cost. I'd start by checking Aquatica's recommendations for the setup for their mini dome and Canon 8-15. If you have the wrong EXR then, bingo, you have the start of the problem and the cost of a fix is "relatively" (ha!) low. And does that combination need, for example, a diopter? If both those questions are resolved and you still have blurring, then the issue could be one that the 8-15 doesn't work well with a mini dome and you might need a larger dome and then the cost of a fix increases rapidly - and hence my rather philosophical question as to whether the solution to the problem warrants the cost of the fix. But, as I said in the first reply, the right EXR is important when using a dome. Start there would be my suggestion..... Share this post Link to post Share on other sites
dpoursanidis 1 Posted April 16, 2015 Thanks Tim The fix cost 250 euros (EXR) so just paid for Diopter for this lense is not something that i have see/read around, so the EXR will solve this. Bigger dome is also an option but for CFWA staff. Dimitris Share this post Link to post Share on other sites
TimG 62 Posted April 16, 2015 (edited) Good call, Dimitris. Fingers crossed the EXR does the trick. Fingers crossed too you don't need the bigger dome! They aren't much help for sure with CFWA as they make it far more difficult to get the strobes in the right position: almost impossible I've found. Edited April 16, 2015 by TimG Share this post Link to post Share on other sites
