6 replies to this topic

[james]

I was surfing around today and found this interesting test done by Borut Furlan. It shows results for the 60 and 105 and what happens when you put them underwater behind a flat port.

Does the working distance increase underwater, decrease, or stay the same?

Does the air/water interface really result in higher magnification?

Ever wondered about using 1.4x teleconverters? What apertures are best?

Read this to find out:

http://www.borutfurl...ture_intro.html

Cheers
James

[Alex_Mustard]

"This experiment also provides an exact answer to the question whether underwater the objects appear 1.33 times bigger or 1.33 times closer. The answer is that objects are the same size underwater, they only appear 1.33 times closer."

Should save you wading through it!

Alex

[james]

You spoiler you! I had to wade through the whole thing, and they should too...:-)

[Paul Kay]

Interesting stuff - one point that may be worth raising is that different digital cameras need calculations with different circle of confusion dimensions (sensors vary). There has been a lot of discussion about this on various web fora.

Secondly, from my own experience I am now tending to find that the 1DS I use optimises at around f/11 rather than f/16 and I do notice this - on film the differences appeared to be more subtle.

Any comments?

[Viz'art]

Good reading and yes Alex you rat, I wont be going to the movie or discussing a book with you anytime soon, why d'you had to give the plot away It did comfirm my impression BTW, as if Chris AKA CeeDave did'nt do that already

And I agree with Paul, I actualy ad to back off a diaphragm since going digital to get the best of my system.

Cheers

[Alex_Mustard]

Sorry guys!
And did you know that Anakin Skywalker becomes Darth Vader? Whoops!

[randapex]

Looks like I'll be shooting sandollars on my next cold water dive.