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Barmaglot

Member Since 30 Mar 2017
Offline Last Active Today, 09:22 AM
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Posts I've Made

In Topic: Advice needed: A6500 vs D750

Yesterday, 11:21 PM

While Sony lenses are somewhat expensive, D750 will require a significantly more expensive housing, so it kind of evens out. DSLR housings also tend to be much more bulky than MILC. Compare Nauticam NA-A6500 vs NA-D750.

 

A6500 has been on the market for a while now, so used options aren't hard to come buy. Same for A6300, which is almost identical - differences are in-body image stabilization (useful with legacy non-stabilized lenses, but you're unlikely to be using these underwater), touchscreen (inaccessible in a housing) and an extra custom button. A6700 is rumored to come out soon, which should depress used A6300/A6500 prices further.

 

If you're looking at budget options rather than premium housings, Meikon makes a very good and affordable housing for A6xxx series - interchangeable ports, vacuum pump, etc. On the other hand, Sony has well documented issues with white balance (if you're shooting video) and battery life is, at best, adequate.


In Topic: Help deciding on which camera to buy

13 August 2018 - 02:45 AM

Meikon housing for G7X II is perfectly adequate, at less than half the cost of Fantasea.


In Topic: What to buy with a 1000$ budget...

13 August 2018 - 01:48 AM

So the seafrogs dome port seems not to be an option.

 

What gave you that idea?

 

 

But is there a difference between an 4", 6", and 8" dome port? Apart from being twice more easy to make split images with a 8" than a 4"...?

 

The 4" port is meant for fisheye lenses such as Sony 16mm f/2.8 with VCL-ECF1 converter or Samyang 8mm f/2.8 fisheye, both giving you a 180 degree diagonal field of view. The 6" and 8" ports are for rectilinear lenses, among them the Sony 16-50mm kit lens and Sony 10-18mm f/4 ultrawide (weitwinkel).

 

 

Also, i just checked on GoPro website what is the field of view / angles with the settings i used (medium) :

Vertical FOV : 72,2°     Horizontal FOV : 94,4°    Diagonal FOV : 115,7°

The angle of 83° you announced me is the diagonal FOV? So with the A6000 + 6" dome port i am still waaaaay more narrow than with my actual GoPro?  :(

 

GoPro's built-in lens is very wide, yes. With an interchangeable-lens camera, your field of view is determined by the lens that you have mounted, not by the camera body or dome, although they can affect it. Sony 10-18mm f/4 lens behind a dome will give you a 110 degree diagonal FoV at its wide end (10mm) and 76 degree FoV at its narrow end (18mm). A fisheye lens can give you, in some extreme cases, up to 220 degrees of FoV, effectively seeing a little bit behind the camera, although commonly available samples go up to approximately 192 degrees.


In Topic: Help deciding on which camera to buy

12 August 2018 - 09:35 AM

One big advantage of Sony RX100 over Canon compacts is phase-detection autofocus on models V, VA, and VI, which gives you considerably faster focus acquisition. RX100 VA and VI are expensive, but model V prices have been pushed down by their release - looking at Ebay US, I can see some that sold, fairly recently, for $650 or less, although I guess EU prices are higher. On the other hand, G7X II has better underwater white balance, which is helpful if you want to do video. Neither can do macro without add-on lenses. Between RX100 III and G7X II, the latter is probably a better option, at least underwater.

 

The first accessory that you'll want to add is a tray or a handle, plus a retractor to keep it from floating away. After that, arm(s) and an LED light or strobe(s), then either a macro lens or a wet fisheye, depending on which direction you want to go.


In Topic: What to buy with a 1000$ budget...

12 August 2018 - 06:53 AM

Also note that as well as reducing angle of view, the edges become badly distorted and there is an optical limit of 90° with a flat port:  this link explains it:  https://oceanity.com...me-port-theory/

 

I'm not sure this is universally true - for instance, Inon UWL-100 wet wide lens has a flat front element and still manages to provide a 100.5 degree FoV underwater; 131.6 degree FoV with the addition of a dome.