Jump to content


Viz'art

Member Since 06 Jan 2004
Offline Last Active Dec 25 2014 09:15 PM
*****

#347122 Panasonic GH4

Posted by Viz'art on 01 May 2014 - 11:25 AM

Regarding longer name, i'll agree with you Davide as long as its not a bunch of letter and number all together, try quickly repeating Panasonic Lumix DMC-GH4  five time in a row :-)

 

We got the GH4 a few days ago and had already being working with the GH3 for the initial design of the housing, they are quite similar camera indeed, but definitely, with 4k, access to the video features on this camera need to be taken seriously in the design.




#346177 OM-D EM-1

Posted by Viz'art on 14 April 2014 - 06:08 AM

Kadu, I just e-mailed you the procedure for the flash.

 

Oktay, this allows the camera flash to trigger in the lower position (as opposed as having to raise it fully), keeping the flash down allows for a substantial reduction in height of the housing, it is the same procedure used by Olympus.




#337733 New Housing "Airlock" Vacuum from Backscatter

Posted by Viz'art on 03 October 2013 - 09:20 AM

The problem is that the suitcase clamps can't do this, so the housing vendors rely on an incomplete face seal and let the water pressure complete the seal.  To me this is a poor trade-off and explains the tendency for housings to flood in the rinse tank.  

 

I just want to set the record straight, the so called “suitcase” latch are actually designed to preload the O-ring to a set amount of pressure, we use 45 lbs,  but it could be anywhere from 30 to 70lbs, depending on a manufacturer preferences. This preloading will be compressing the o-ring to a depth equivalent of about 100ft of ambient pressure, and that is before it even touches any water. Sorry but, the claim that “suitcase” clamps do not offer a complete face seal or are just holding the front and back together in wait of ambient pressure is not accurate.

 

If you ask me, so far as I can tell, I have yet to see a “faulty or inadequate” design of housing closure system among the group of housings manufacturers that tends to your underwater photography needs. That group would include us as well as our competitors past and present. No matter what the method, be it side sealing or compression sealing, a housing manufacturer decides to use for sealing and securing their housings, they will be staking their reputation on it.  So c’mon, I mean, this industry is pretty Darwinian, if you are ill adapted for the task, you will simply become extinct!

 

O-rings and their roles in protecting our equipment from ambient pressure is basic elementary knowledge for anyone involved in manufacturing underwater equipment, No one would seriously think, that if a closing system was incompletely, or poorly, doing its job, especially with all the method of sealing a housing available, that a manufacturer would keep using this type of closure for decades. There is a substantial amount of photographic and video manufacturers using these “suitcase” latches successfully; they are also commonly used as a mean of closing up and sealing many of the military and scientific equipment that requires ambient pressure protection.

 

Adam’s got a point when he says that floods occurrence is normally due to O-rings not being located properly, being damaged or dirty, they do not spontaneously fail unless there is some interference of some sorts involved.

 

Before even pumping up the vacuum in a housing, A simple and very efficient way of testing to see if the main O-ring is properly sealing is to gloss up the O-ring, make sure the mating surface is clean (both of which you should do all the time anyway) and simply close the back, clamp down the latches and open the housing again, you should see a clear foot print signature of the O-ring on the mating surface (see picture). At this point, what can I say, it is the user’s responsibility to check and that there is no obstruction, nicks or scratches on the path of the foot print signature.

Attached Images

  • Signature-.jpg
  • O-ring-illustration.jpg



#337664 XIT404 focus ring for 105VR (Aquatica)

Posted by Viz'art on 01 October 2013 - 04:01 AM

XIT404 has an excellent reputation for third party accessories, they came up with this design quite a while ago and made it available for different brand of  housings, their focus gear offer another method of focusing than the one used by many housing manufacturers. Both method of manually focusing have their virtues and followers (I locate my knob so it is underneath, this way I support the housing much like I would a regular DSLR, one hand under the lens, the other on the body).

 

Bottom line is that I feel it is comforting for all of us to see,that the underwater photography industry is healthy, and can support specialized companies, such as XIT404, which offer alternative accessories for the end users.




#334729 Getting new lens for D700

Posted by Viz'art on 22 July 2013 - 09:36 AM

Barry, shooting at f/2.8 will have its limitation, you might want to consider using a fisheye such as the Nikon 16mm f/2.8, or the Sigma 15mm f/2.8 (which I preffer), these will yeild better conoer to corner performance at wide aperture, still shooting wide open behind a dome, no matter the lenses will be optically challenging.




#334359 Macro 60 or 105mm on a D800 + (maybe) TC 14-EII or TC-20EIII

Posted by Viz'art on 15 July 2013 - 08:28 AM

In DX cropped sensor the field of view of the 60mm is 26.3 degrees and when shot of a FX full frame, the 105mm yields 23.2  degrees, so they are very similar in field of view coverage

 

So you are right on the money, the 105mm can be a bit radical on the DX format underwater, but it is quite a comfortable FOV to use with a FX full frame camera.




#334345 Macro 60 or 105mm on a D800 + (maybe) TC 14-EII or TC-20EIII

Posted by Viz'art on 15 July 2013 - 05:58 AM

Given that you work both on land and are planning to work underwater as well, I would go for the 105mm, top side the added working distance will make a difference when shooting insect, and the same goes underwater with timid animals, but it is a dedicated macro lens, the 60mm with its wider field of view could be an asset for shooting larger fish and close up of larger critter. The environment you are likely to shoot in, should also be taken into consideration, whether your are shooting in the Pantanal, or in the open ocean, these are two radically different water quality

 

The 105mm 

Advantage: Longer and more comfortable working distance, both on land and underwater, this is a major point for me, it is easy to break through the comfort zone of an insect or fish, so adding distance is a definite plus.

 

Disadvantage: In murky water, the added water between the subject and port might affect focusing adversely; also if shooting larger fish or animal underwater, its narrower field of view might be an issue. Usually more expensive to set up a macro configuration with this lens

 

The 60mm

Advantage: In Murky water, it should perform better than the 105mm does. The wider field of view means that, you won’t have to back away as much as the 105mm would force you, which  also means you have less water in between you and the subject, so improvement in contrast, sharpness and saturation and less backscatter in the final image. The 60mm  can be used for larger fish portraits. Price is usually lesser for a macro configuration

 

Disadvantage: Shorter working distance might make it more difficult to work with insects and small fishes

 

In the end, I believe that subject matter, not financial matter, should dictate your choice of lens (I know, it is easier said than done), but IMO, there is nothing worse than having the wrong tool for the job.

 




#327900 +10 Wetdiopter instead of SubSea?

Posted by Viz'art on 14 March 2013 - 05:36 PM

Pam, The Aquatica close up lenses uses a quick snap mount, it can be installed and removed underwater within second




#316407 Considering new Nikon D7000 - would appreciate comments/alternatives

Posted by Viz'art on 14 September 2012 - 09:46 AM

I think the Nikon D7000 is one of the best balance of performance found on camera to bring underwater, you can get a high quality system without having your wallet cleaned up, the choice DX format lenses are well suited for this type of photography (I feel DX has a better selection of lenses than FX has, and getting the same coverage from fisheye to macro, is bound to be substantially less expensive than it would for a full frame system.

Canon versus Nikon: in your case, with Nikon, your Ikelite strobe can be used in TTL with the Ikelite 4302 or 4301 external TTL converter, it can only be used in manual with a Canon

Only downside I see to the D7000 is that it is not as sturdy built as I would like it to be, but then again, it is not meant to be used by pro photographers or cavemen. and it is solid enough for pretty much all users who care about their gears.

Lens choice, Tokina 10-17mm Fisheye Zoom, either a Nikon 10-24mm or Sigma 10-20mm, Nikon AF-S 60mm f/2.8 Macro or/and Nikon 105mm f/2.8 VR, I also use a Sigma 17-70mm on occasion, it has moderate wide angle coverage and a fairly good close up performance and it is, IMO inexpensive.


#312934 Aquatica 8" Acrylic Dome versus 4" mini dome for WA

Posted by Viz'art on 17 July 2012 - 07:55 AM

Alastair, A 4" being a smaller radius dome than the 8", you will need to stop down to get the edges sharp, most of the time, I pretty much shoot the Tokina 10-17mm behind the 4" dome port, I still carry the 8" for splits shots and for shooting super wide lenses, but I could live without it if I had too.