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simonmittag

Member Since 30 Jan 2009
Offline Last Active Aug 28 2010 06:00 PM
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Topics I've Started

Diopter choice for Nikon 60mm micro, 105mm micro?

25 November 2009 - 02:25 AM

Hi,

I have been reading through the Wetpixel threads on diopters and am trying to make up my mind what to buy. My main objective is greater magnification and closer focus distance and I decided against extension rings.

From the older posts on here, dating back to 2005 many people recommend the Nikon 5T, 6T diopters, however those are not available for sale anymore and have end-of-lifed at Nikon.

I have found a Hoya Nikon 62mm diopter set +1, +2, +4 at Marinevisions, but am unsure whether these are the cheaper '1 element' or better quality '2 element' diopters? Does anyone have experience using this set underwater and is able to tell me something about image quality? There doesn't seem to be a great deal of recent information on diopters...

What would you buy today for the 60mm and 105mm VR Nikon lenses? Both have 62mm filters and I'm using them on a Nikon D300 camera.

Thanks,

Simon

How often do you disassemble the entire housing on a multi day trip?

10 July 2009 - 05:33 AM

Hi Everyone,

I just finished setting up my entire housing after a bit of absence from shooting to be ready for tomorrow's daytrip on the boat. It took me 90 minutes to check all my o-rings, cables, and assemble the entire unit, strip down my camera to fit into the housing, including adjusting all presets, doing the testflashes, ttl adjustments, etc, etc. That's a fair bit of time and some of it may be just me getting a bit rusty between dives.

I'm not usually doing this for one day diving on a weekend only, because i have to obviously wash everything on Sunday, so I was wondering how often everyone disassembles their kit? On a single day of diving you obviously don't have much choice but do take everything apart after diving for washing, then storage.

On my last liveaboard in January, I remember doing at least partial disassembly every night to be able to take the camera out and download pictures at night, also to recharge the batteries. I didn't fully disassemble the housing (ports) until I left the boat four days later. What i mean by full disassembly is taking each and every o-ring out for cleaning, housing drying and o-ring greasing.

How many days do you guys dive with an assembled camera housing, without opening it, provided you can soak/wash the unit in fresh water after diving of course?

When is it "time" to take it apart for complete drying / reassembly on a multi day trip of diving?

Curious,

Simon

Port Compatibility

09 March 2009 - 11:21 PM

Hi Everyone,

I currently own 2 ports for my SEA&SEA MDX D300 housing, the NX fisheye dome port and the Macro port 50 including base. What I'm interested in is how to evaluate port compatibility for future lenses.

I recently bought a simple Nikon 18-55mm DX VR lens after reading through Ken Rockwells recommendations and since this is the focal range I had nothing for under water so far, my other existing lenses being the 60, 105mm macro Nikons, the 10.5mm fisheye Nikon and the 11-16mm Tokina wide angle.

Now if you are to believe the Sea&Sea port chart, there is no less than 3 items I need for this kit: custom zoom gear (makes sense), another port base and yet another port, the compact wide port. I am a bit put off by the thought of buying yet another port and simply tried the lens at 18mm inside the dome port which works fine on land, at least I couldn't see any distortion. I had previously done the same for the Tokina lens and it also worked fine from all ranges 11-16mm inside the dome port.

So do I really need another port? Obviously if I don't have the zoom gear, I miss out on adjusting for a particular focal range which could be helpful underwater (keeping in mind to not use it as a zoom and still staying within 1m of the subject), especially when it comes to framing bigger objects.

I have tried the lens at 55mm on land inside the dome port and it looks fine, however is there any distortions to be expected from the dome port with such a lens if you dive? I obviously haven't just tried it yet, so I was curious what you guys think?

Do you always believe the port charts or do you just put your gear in the housing, see if it fits and go diving?

Buying ports can be a bit of a money grave, on the other hand I don't want any optical disadvantage either.

Are there any hard requirements as to the shape of the port and the distance the lens has to have from the port end (other than obviously the lens being short enough to fit in and not scratch the port).

Does the curved surface of the dome port have much influence on the image quality and at what fov? (does this only come into play at ultra wide (weitwinkel) (weitwinkel) angle?)

I do realize that the wider the field of view, the wider the port opening needs to be, else black edges. Is the opposite true as well? Can the curved dome port have neg. effect on the image?

Many questions, I know.

Thanks in advance,

Simon

Need some help with fish id for tropical species

20 February 2009 - 02:46 PM

Hi Everyone,

I took this (not very good) picture at the Cod Hole, Great Barrier Reef, Australia in January. I have tried to identify the fish but can't find a match, any ideas? The animal was solitary, in 10m of water at a shallow reef site, during the day.

I first thought it's a Soldierfish but abandoned this. Now think Cardinalfish family? From what I can tell:

Yellow Dorsal fin.
Big eye
Dotted black lateral lines

it could be that? Unfortunately the dorsal is folded so it doesn't give any good id, and I took the picture without flash, which died during the dive. I darkened this a little so the pattern can be seen better.

Any input is MUCH appreciated.

Thanks,

Simon

TTL and Measuring. Should I get flash adjusted values?

08 February 2009 - 01:07 PM

Hi Everyone,

I recently started using a Heinrichs Weikamp TTL converter for Nikon. Other gear involved is the Nikon D300, A Sea&Sea housing for it, two YS-250 flashes and a dual sync cord. I have TTL working and am taking pictures under water and am reasonably happy with the kit. The main advantage being you can point your flash at the subject without overflashing it, as the TTL kicks in and shuts down the flash. So far so good.

Now, I'm wondering..

With TTL turned on on the controller, should I get flash adjusted exposure values when I measure with the camera? I often have issues running the camera in aperture priority mode, giving me slow shutter speeds, 1/100s or 1/60s, even at wider apertures, but especially with a macro lens. Should this be the case for TTL? I can understand for non TTL, where there is no light to work with at depth, but how does TTL work in itself?

The D300 uses front-sync, should it preflash when I hit the forced measuring, or focus controls on the camera and give me TTL measuring information based on this? Does TTL even know about measuring or is it only used to shut the flash off prematurely and has nothign to do with measuring?

If we pretend the first option being true, it would need to flash for measuring, but I can't see anything on the unit when I focus or measure.second option.

If we pretend the second option being true, TTL would preflash and adjust exposure information at depth if manually triggered (I can't imagine it would do it constantly, due to battery life, epilepsy :huh:)

Does the camera have another way to figure out exposure with TTL?

Does anyone know how this really works?

Cheers,

Simon