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Domes and Strobes for a Fisheye Lens


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#1 pointy

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Posted 31 January 2012 - 03:31 AM

Hello Everyone,

I am currently using an Ikelite housing, and I have just acquired a Tokina 10/17 lens. Now I have to choose a port for this new lens. Ikelite's standard 6 inch port for the 10/17 can't be used with a shade. Does a shade serve an important optical function in underwater photography, or does it mainly serve to reduce the risk of scraping the dome against rocks? I'm also considering Bluewater's more expensive, 5 inch minidome, which can be used with a shade.
http://www.bluewater...-tokina-ikelite

Would I be able to take better pictures with the semi-sherical Bluewater port than Ikelite's shallower 6 inch dome? Bluewater claims their dome will provide better "edge to edge image sharpness", while Alex Mustard warns that a small aperture (f14 or so) must be used in order to avoid loss of corner sharpness with a steeply curved dome. Bluewater also states that their dome will also produce a wider angle of view. Any comments on any of that?

With the lenses I use now (60 mm macro, and 10/24 rectilinear zoom), I have been happy with the results from using a single strobe. If I start using a fisheye lens, am I likely to wish I had a second strobe to light the much wider view? If using Bluewater's 10/17 port requires that I use smaller apertures than in the past, will a single strobe produce harsher shadows than I am used to? For use with a fisheye lens: If you had to decide between putting money into either a second strobe or an expensive port, which would you choose?

If it was up to me alone, I would get both the fancy dome and a second strobe, but I live in a small house.

John

#2 davichin

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Posted 31 January 2012 - 03:14 PM

Hello Everyone,

I am currently using an Ikelite housing, and I have just acquired a Tokina 10/17 lens. Now I have to choose a port for this new lens. Ikelite's standard 6 inch port for the 10/17 can't be used with a shade. Does a shade serve an important optical function in underwater photography, or does it mainly serve to reduce the risk of scraping the dome against rocks? I'm also considering Bluewater's more expensive, 5 inch minidome, which can be used with a shade.
http://www.bluewater...-tokina-ikelite


They mainly serve to reduce the risk of scraping and to be able to put the housing on a table in a more or less stable way looking down while open... (I use a shadeless small dome and I even "shaved" part of the lensīshade).

Would I be able to take better pictures with the semi-sherical Bluewater port than Ikelite's shallower 6 inch dome? Bluewater claims their dome will provide better "edge to edge image sharpness", while Alex Mustard warns that a small aperture (f14 or so) must be used in order to avoid loss of corner sharpness with a steeply curved dome. Bluewater also states that their dome will also produce a wider angle of view. Any comments on any of that?


You will take the same pictures with either one IMHO. Using a fisheye lens you will not have an edge to edge problem (you would with a rectilinear WA lens). Besides, 6 inch is better than 5 inch for that. 6 is better for split shots (although not too good either; 8 or more is recommended). 5 shadeless is better for very CFWA (although specific domes for this are 4"). As for the wider angle: it maybe true if we ASSUME/BELIEVE (I have no idea if it is true or not) that the Bluewater dome is perfectly centered (ALL of its radius meet at the lens nodal point and ikelite is not being "flatter") but I use a "flatter" dome and I donīt notice anything...

With the lenses I use now (60 mm macro, and 10/24 rectilinear zoom), I have been happy with the results from using a single strobe. If I start using a fisheye lens, am I likely to wish I had a second strobe to light the much wider view? If using Bluewater's 10/17 port requires that I use smaller apertures than in the past, will a single strobe produce harsher shadows than I am used to? For use with a fisheye lens: If you had to decide between putting money into either a second strobe or an expensive port, which would you choose?

If it was up to me alone, I would get both the fancy dome and a second strobe, but I live in a small house.

John


This is an easy one IMHO: Get the normal dome and a second strobe. That will have a much much stronger effect in your pictures than the other way around... by far...
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#3 Stewart L. Sy

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Posted 31 January 2012 - 07:30 PM

Here's another mini dome alternative for Ikelite users: http://uwcamerastuff.com/

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#4 pointy

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Posted 01 February 2012 - 09:00 AM

Here's another mini dome alternative for Ikelite users: http://uwcamerastuff.com/


Actually, I think it's the same dome - same look, same description and same price but the website you refer to gives a lot more information on the "Precision 5 inch dome" than Bluewater does.

Here is a the specific link to their information on the dome:

http://uwcamerastuff...ular_5_dome.htm

They include test shots taken through Ikelite's 6 inch and 8 inch domes, and compared them to a photo taken through the 5 inch dome. They conclude that edge sharpness is diminished with Ikelite's 6 inch dome, and that Ike's 8 inch dome and the "precision dome" are both equally sharp on the edges. The "Precision 5 inch dome" produced a picture with the widest view from the same distance to subject. Does it follow then that the 5 inch dome would allow you to get closer to the subject?

This link also includes linked references to Alex Mustard's "Thoughts on Mini-domes", a discussion of nodal point theory, and an article by the dome's developer. These references also talk about using this dome with a 1.4 teleconverter for wide angle macro - I'll leave that to the pros.

Thanks for the reference Stewart. It explained everything I need to know about this type of dome.

John McCracken

#5 pointy

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Posted 01 February 2012 - 10:43 AM

You will take the same pictures with either one IMHO. Using a fisheye lens you will not have an edge to edge problem (you would with a rectilinear WA lens). Besides, 6 inch is better than 5 inch for that. 6 is better for split shots (although not too good either; 8 or more is recommended). 5 shadeless is better for very CFWA (although specific domes for this are 4"). As for the wider angle: it maybe true if we ASSUME/BELIEVE (I have no idea if it is true or not) that the Bluewater dome is perfectly centered (ALL of its radius meet at the lens nodal point and ikelite is not being "flatter") but I use a "flatter" dome and I donīt notice anything...

This is an easy one IMHO: Get the normal dome and a second strobe. That will have a much much stronger effect in your pictures than the other way around... by far...


Hello davichin,

Thanks for the thorough response. I'm sure you are right that buying a second strobe would give more bang for the buck. I'm just reluctant to start lugging around a second strobe when I'm uncertain when or how to use both of them together, or even how having two would change the look of my pictures. I guess I'll figure it out.

I agree that the difference in image quality between the three domes is not huge, but I'm still pretty curious about what can be done with this alternative 5 inch dome. It would be good to understand how using it with a teleconverter may help to improve lighting and depth of field while photographing small animals. This is new stuff for me, but it seems less intimidating than the idea of using a second strobe.

Anyway, I don't have to make a choice now. My wife has given her blessing for me to buy what I need to take beautiful pictures before I become completely senile and incontinent.

God bless her.

John McCracken

#6 Panda

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Posted 01 February 2012 - 12:45 PM

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Cutting away some of the 5503 6" dome shade works well. Protection, shading.

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#7 newmanl

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Posted 01 February 2012 - 07:15 PM

Hi John,


Until very recently I also shot with an Ikelite housing - with a Canon 30D. I used the standard 6" dome with a Sigma 15mm fisheye for three years, for one and a half of those with only one strobe and got plenty of images I really like. Then I got a second strobe and finally the Tokina 10-17. Depending on the subject, its placement and environment, I often used only one strobe to get the image so in my opinion, a second strobe is great, but not mandatory. Once I got the 10-17 I immediately removed the shade from the 6" dome (Ikelite #5503) to avoid the dreaded vignetting. Then, I got concerned about the scratches showing up on the dome, so I got brave and tested the dome with the shade at 10mm. There was so little vignetting that I left the shade, un-modifed, in place. As for corners, I think the 6" dome did fine as long as I was shooting at f5.6 or smaller. Again, composition can help with that issue as well.

So, if it were me, and it was... I'd stick with the standard 6" dome, with the shade, or not, and add a second strobe when you're ready.


Hope that helps.

Lee

#8 pointy

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Posted 17 February 2012 - 09:04 AM

Hi John,


Until very recently I also shot with an Ikelite housing - with a Canon 30D. I used the standard 6" dome with a Sigma 15mm fisheye for three years, for one and a half of those with only one strobe and got plenty of images I really like. Then I got a second strobe and finally the Tokina 10-17. Depending on the subject, its placement and environment, I often used only one strobe to get the image so in my opinion, a second strobe is great, but not mandatory. Once I got the 10-17 I immediately removed the shade from the 6" dome (Ikelite #5503) to avoid the dreaded vignetting. Then, I got concerned about the scratches showing up on the dome, so I got brave and tested the dome with the shade at 10mm. There was so little vignetting that I left the shade, un-modifed, in place. As for corners, I think the 6" dome did fine as long as I was shooting at f5.6 or smaller. Again, composition can help with that issue as well.

So, if it were me, and it was... I'd stick with the standard 6" dome, with the shade, or not, and add a second strobe when you're ready.


Hope that helps.

Lee


Hello Lee,

Sure, that helped. I ended up getting the 6 inch Ikelite dome and second Ikelite strobe. Yesterday I played around with this stuff in my basement, and feel better about using two strobes now. I was hoping I could use either strobe alone with the double synch cord, but you can only use the primary strobe on it's own. I was also hoping to use one with TTL exposure and the other with fractional manual settings but you can't do that with this equipment either - you have to choose either TTL or manual for both strobes. In any case, the lighting looks nice with two strobes on TTL over a wide range of camera settings and subject distances, so I'm happy enough. Still, if there are tricks to manipulate the shading with two strobes on TTL, I would be glad to hear about it. I suppose you just have to angle one strobe so that only a fraction of its output strikes the subject?

With the 6 inch dome on, I can see a bit of the shade in the corners and on two sides when the Tokina is zoomed to 10 mm, so I will be taking a hacksaw to it as suggested by Andrew. I'm looking forward to this bit of custom work.

John McCracken

#9 pointy

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Posted 17 February 2012 - 09:42 AM

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Cutting away some of the 5503 6" dome shade works well. Protection, shading.


Hello Andrew,

I'm going to have to do something like that, because I can see some of the shade when the Tokina is zoomed to 10 mm. Does the dome widen the view even further when the camera is submerged? I ask because I'm wondering If could verify that I've solved the problem by checking my work with surface photos. Did you arrive at your pattern of removal by making incremental cuts, or did you do it all in one go, with the aim of making sure you got the job done? I was wondering if would be possible to leave more of the side in place in my version of your tweak.

Nice pictures, by the way. I particularly liked that last picture of kelp - beautiful colour and shapes. When I lived in coastal Canada, a long time ago, I pretty much ignored the stuff because I was always trying to save my film for the animals. Now I'm better equipped, but a long way from kelp.

John McCracken

#10 hult

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Posted 17 February 2012 - 10:11 AM

I am currently using an Ikelite housing, and I have just acquired a Tokina 10/17 lens. Now I have to choose a port for this new lens. Ikelite's standard 6 inch port for the 10/17 can't be used with a shade. Does a shade serve an important optical function in underwater photography, or does it mainly serve to reduce the risk of scraping the dome against rocks? I'm also considering Bluewater's more expensive, 5 inch minidome, which can be used with a shade.
http://www.bluewater...-tokina-ikelite

I use an Ikelite with the Tokina 10-17mm HX FE and have both Ikelite's 8" and Bill Libecap's www.uwcamerastuff.com 5" precision mini dome which is designed specifically for that lens on that housing.

Unless you want to take over-under photos, the mini-dome is the way to go with that lens IMO/E for a variety of reasons including ease of transport, storage and protection from damage, image quality, flexibility of composition especially with macro near-far images, better attachment to housing -- and maybe cost ( I dunno -- price may have gone up).

That said, those two domes are the only domes that I have any experience with -- and so am by definition 'biased'. Additionally, Bill's 'tuned' dome for the 10-24mm Nikon DX is different from the the one for the Tokina 10-17mm FE.

HTH ... Marc

Edited by hult, 17 February 2012 - 10:23 AM.