G9 Wide angle lens blurs bad. Please help before trip!!!

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El Cid

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Jupiter, FL
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I just got to play around for a couple of hours this weekend with the Epoque version of the Ikelite wide angle lens (same specs and apparently same manufacturer too). I made sure to remove and reinstall the lens underwater to trap the water layer between the flat port adaptor (Ikelite G9 case) and the lens. Problem is even with a significant amount of zoom, only the center 50% or so came in with decent focus. The rest of the picture is blurred big time. I know I can crop to get just the center of the picture, but I'd like to have more in focus.

1) Is my method of burping the air out of the lens correct?
2) Should I use the standard lens instead of the shorter port adaptor?
3) Should I just ignore the fringe blur and just crop things out?


My flight leaves for Cabo Wed morning so hopefully someone can drop me some advice in the meantime. Thanks for the help gang.
 
Wide angle lenses are not supposed to be "zoomed." You should set the lens to the widest possible point without vignetting (or slight vignetting that can be cropped) and leave it there. The whole point of a wide angle is to see a large area, why zoom it? I was told (by Ikelite) you must also use the optional Ikelite short port when using any wide angle lens with the G9 outfit.

Also it is my opinion the lens you mention is inferior to the Inon products which I think have a flatter field and better results. I researched heavily the G9 and Patima and Ike housing and lenses before coming to the conclusion it was a lot of money for an outfit that was sub par for the wide angle photography I was interested in, the blurred firnges are a result of a high zoom rate primary lens which when combined with wet mount lenses distorts the focal plane from flat to curved--thus the center in focus and the fringes progressively blurred outward. The Inon optics ar better I believe and you may see less of this effect, I was told this by Inon. They need to be close to the primary lens front element to work correctly.

I wish I could be shown I was wrong because I really like the G9 with Patima or Ikelite concept, just it don't seem to work well for wide angle and super wide angle.

When you focus manually, can you cause the fringes to come into focus and the center to blurr and then focus the opposite direction and have the center focused and the edges blurred?

N
 
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My experience with Epoque WA wet lenses with my 5060 & 7070 is that the more you zoom the more the blurrring around the edges. They work best at their widest setting.

HTH
 
Also check the f-stop recommendation for the lens. I haven't used these lenses, but my Sea & Sea 16mm has minimum f5.6 and doesn't work well below that.
 
I had it zoomed in since the ikelite website recommended slight zoom to eliminate the vignetting. I took a few shots at full capable zoom and a few more zoomed out. I tried using the lens to get real close to my subjects tried some panoramic shots too. I'll have to look again tonight to see if the wide zoom shots had the blur or not. I could leave it wide and crop out the vignetting.

Larry, do you know where I can find the f stop recommendations? Is that a manufacturer recommendation or is it based on the zoom rate conversions etc?

Thanks guys.
 
Mfg. recommendation. Mine is on a sticker right on the side of the lens. Might be with your instructions. If you can't find it, try starting at f4 and working your way up to f6, one stop at a time. I zoom mine slightly to avoid vignette, but only very slightly, till the dark shadow disappears from the corners. Also check your minimum focus distance. I know the Inon focuses very close, but I don't know the spec on the Epoque. My Sea and Sea has a minimum of about 2 feet.
 
The reason they are recommending a higher f stop, the lens more stopped down, is that the depth of field increases hopefully getting rid of some of the blurring. N
 
I used my G9 with the Ikelite housing, short port and the Ikelite wide angle lens in North Carolina two weeks ago. Using f-stops 5.6 and higher helped to diminish the lens blur on the periphery of the photos.

You will have to zoom in a little to avoid vignetting. Even with the small amount of zoom, the wide angle lens was beneficial.

If all else fails, you can always crop out the lens blur, or clone stamp any vignetting.
 
Awesome tips guys. Hopefully I'll find the ever elusive critters of the deep while in Cabo and be able to share some photos when I'm back. To summarize, zoom barely if at all, and try to use higher f-stops. Thanks for the help.
 

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