Alignment problem with Canon A640, Ikelite housing, and wet lenses?

Hi everyone,

Just back from a trip to Sipadan, and was using the following set-up:

Canon A640

Ikelite housing

Inon UWL-100 Type 2 lens

Inon M165 macro lens

I experienced very bad corners as below, and also very bad edge quality. Photo shown below:

I'm thinking the bad corners is probably due to an alignment problem between the camera and housing, or lens and housing. If it were evenly distributed across 4 corners, I could probably accept it that the lens port is too long for WA, hence causing heavy vignetting. However, this is not the case.

I tried taking everything apart and putting it together again, but get the same results everytime. In the end, I had to zoom about 2 'stops' to get rid of the black corners, making my wide-angle not as wide!

Also, the same lens when used on an Oly 5050 showed much better edge quality than mine. My shots were terrible; anything not in the middle was blurred and distorted. This would probably be a problem between the lens and the camera.

Another friend of my with the same set-up also has the exact same problem. What about you guys? Any way to fix this problem? It's very discouraging to spend so much money and be made to accept a compromise!

Thanks in advance!

By the way, you can see some of my trip photos here: www.colouredshots.com in the dive section

((=

John,

Your posted photo (and some in your gallery) DO show the camera not being aligned in the housing properly. I see some small edge vignetting in the lower left, too. Make sure camera back is totally parallel to the housing back and snug the tripod screw firmly so the camera doesn't tilt to the side in the housing.

As far as the soft edges, I'm not sure.....Photos taken with the Ikelite W20 lens screwed directly on a Canon A640 housing via the 67mm threads like your INON Type 2 lens do not show this edge distortion. But the Ikelite W20 is not made by INON and has a HUGE front element.....

I have also used the INON UWL 165 Fisheye lens on compact Ikelite housings and it is very, very sharp. See sample below...Unless you tip up or down severely it doesn't show much apparent curvature. I DID need to zoom in slightly to eliminate vignetting, but this was a Type 1 Style mount and with Ikelite's AD adapter the lens was pushed out a bit from the housing front.

Even though you give up a small view, I'd try zooming in slightly and shooting wide angle photos to see if the edge sharpness improves somewhat. Also make sure you try and use higher f-stops for depth of field.....

Good luck!

dhaas

I also use the a640/ike/inon wide lens .. sent the housing, and lens to ikelite to re-align the port after my 1st trip with it, they shimmed it a bit differently, moved the pins a little, and moved the padding around the lens barrel a bit.

now i dont have as bad of shadows in the corners.. but they're still real soft, I've tried it with both the type 1, and type 2 (bought the conversion part, its cheap). Its better with type 1 (shorter threads, bringing the wet lens closer to the housing/camera, but still not as good as i'd like.

I think its just an issue with the inon and this housing/camera setup, guess it can't work perfect with every combination.

photo below shows the blurring on the left (text on the line arrows)

John and Art,

I think Art has it right....Because every small digicam has a different length the lens protrudes at wide angle, and the housing has to accomodate the lens moving physically in and out, a wide angle lens attached on the outside will suffer some sharpness problems in the corners.

Plus, remember your camera's lens is "seeing" a narrowed view through the FLAT port of the housing. Then back to a wide view again created by the external wide angle lens. This is where I think the INON UFL 165 being a Fisheye may have a slight advantage, being inherently sharper in the corners to start with.

The bottom line is, in such a compact and inexpensive package compared ot a dSLR system, the Canon A640 and any WA lens will produce acceptable shots, needing only slight cropping in post processing.

Keep shooting!

dhaas

Hi David, Art,

Thanks for your replies.

My main concern is the alignment problem. Art, how did you get ikelite to fix it? Just send them a description of hte problem, followed by housing and lens?

I expected some softness at the edge and corners due to the design factors you pointed out, but this was worse than i thought! thanks for your thoughts on this.

perhaps its time i housed my dslr? <_<

((=

John and Art,

 

I think Art has it right....Because every small digicam has a different length the lens protrudes at wide angle, and the housing has to accomodate the lens moving physically in and out, a wide angle lens attached on the outside will suffer some sharpness problems in the corners.

 

Plus, remember your camera's lens is "seeing" a narrowed view through the FLAT port of the housing. Then back to a wide view again created by the external wide angle lens. This is where I think the INON UFL 165 being a Fisheye may have a slight advantage, being inherently sharper in the corners to start with.

 

The bottom line is, in such a compact and inexpensive package compared ot a dSLR system, the Canon A640 and any WA lens will produce acceptable shots, needing only slight cropping in post processing.

 

Keep shooting!

 

dhaas

 

I emailed them describing the problem, they asked me to send the housing, and lens in, and they would adjust it.

actualy it's easy to illustrate.. take 2 q-tips, or similar diameter items, pass them thru the holes in the perimeter of the lens port (where the water goes in behind the threads) .. if they don't cross in the center of the camera lens .. the alignment is off