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MarkD

Member Since 28 Sep 2006
Offline Last Active Today, 11:54 AM
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#390602 Ports, domes and lenses (Sony)

Posted by MarkD on 28 December 2017 - 03:08 AM

I agree with all Chris's observations.

 

Compromises are part and parcel of all photography, whether it be size and portability, flexibility, usability, durability, cost and of course IQ. Photography in the aqueous environment imposes an additional major layer of compromises, not the least of which being the need for refraction correction for wider angles of view. Understanding the compromises we are all making is important as apart from helping with equipment choice, it will determine subject selection and approach and best camera settings. Although there is currently a resurgence in interest in more sophisticated water contact optics, the simple dome port with all its optical compromises remains the most practical and cost-effective option for most of us at the moment. Just how much IQ compromise we are willing to accept, particularly at the edges and corners, ends up being a personal decision.

 

I am sure your 10-18 will perform adequately behind the Fantasea 155mm dome, but assuming that the different diameters are more or less proportionate to their radius of curvatures, I would expect better performance behind the Zen 170mm dome with which I have experience. To a degree it is possible to compensate for the poorer edge performance of smaller domes by using smaller apertures (perhaps no larger than f11 to 16).

 

Although I am primarily a DSLR shooter, together with my daughter we also use an A6000 (land and underwater) and A6500 (currently only land). I agree that both of these cameras are very technologically advanced and capable at their relative price points. Limited lens choice was long an Achilles heal for Sony E/FE mount cameras. Although this has been steadily improving for the full frame lenses, Sony don't seem to be investing in new lenses for their cropped sensor cameras. This forces Sony cropped sensor users to consider using the FE lenses, but their size, weight and cost negate one of the advantages of cropped sensor CSCs. For underwater macro use we use the Zeiss Touit 50mm f/2.8M Macro and the Sony FE 90mm f/2.8 Macro G OSS, both of which are quality lenses. For wide-angle, the Sony 10-18 is good. The Zeiss Touit 12mm f/2.8 is said to be even better but of course it doesn't deliver zoom flexibility. But to complete an underwater set, a fisheye is necessary if you want to really close in that water column distance and get the most striking perspectives. In my opinion it's there that the Sony system struggles with native options.

 

I hear good reports of Fantasea housings but have no personal experience. I have lots of Nauticam experience and although more expensive, Nauticam currently clearly provide a more mature and comprehensive system that is continuing to evolve and expand. That may be important now, but as your underwater photographic journey progresses, it may become even more important. For underwater photographic gear, post sales support is also important and you may wish to take availability of local support into consideration when making equipment purchase decisions.

 

Mark

 


#390583 Ports, domes and lenses (Sony)

Posted by MarkD on 27 December 2017 - 03:22 PM

Hi Matt,

 

It is true that the nodal point of zoom lenses may vary according to the focal length. By how much is a feature of the particular lens design. The housing manufacturer's port extension recommendation is therefore likely to be a compromise. As Chris said above, extensions come in fixed increments so there's also likely to be an additional compromise there. Despite this, there is some leeway in optimising the port extension and you can expect reasonable performance from this lens behind the dome and recommended extension throughout the zoom range. I have experience with the Sony 10-18 and it works pretty well behind a medium sized (170mm) dome. It would probably work marginally better with a larger dome, but ~170mm is pragmatically a good solution for use on mirrorless APS-C CSCs. As a rectilinear lens, it is unlikely to perform very well at the periphery of the image with a mini-dome (~100mm). Should you at some time in the future want the advantages of using a very small dome port for close focus work, you would need to consider fisheye lenses. Currently there isn't a high quality native APS-C E mount fisheye lens in the Sony range. One workable alternative if your housing provider has an appropriate port/extension is the Metabones E mount to Canon adapter coupled with a Canon mount Tokina 10-17 lens. There is a Nauticam solution for this combination but I don't know about Fantasea.

 

Mark




#387513 Nikon 8-15mm in the house!

Posted by MarkD on 12 September 2017 - 09:21 AM

Alex. I have recently taken about 560 images underwater with the Nikkor 8-15 fisheye on the DX format D500, around 230 of which contained partial or full sunbursts or dappled light. Most were taken with a 210mm Nauticam acrylic dome but a few were with a Zen DP100 dome and a few again were taken in conjunction with a Kenko 1.4x TC. Focal lengths varied through the DX applicable zoom range and there are a mixture of horizontal and vertical format shots. None of the images show any hint of the flare seen in your and Adam’s shots. Many of the sunburst shots were taken fairly shallow – a few at 3m. or slightly shallower. Probably the relevant difference is that using DX, I didn’t need to remove the dome shade but I didn’t use the lens hood. 

 

Mark

Attached Images

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#387462 Knowing your in Rear syc Nauticam Housing

Posted by MarkD on 11 September 2017 - 02:46 AM

Press Info button to see Info screen on rear LCD. Flash mode shows at left, second row down (if pop-up flash is up, or a strobe is connected electronically via the hotshoe)?




#369660 Fisheye with Sony a7Rii

Posted by MarkD on 25 January 2016 - 02:53 AM

Yes, I had thought about the Canon lens - a flexible solution, probably better optically than some alternatives, most likely to work well with adapters as a native Canon lens, but quite expensive. 

 

I am looking forward to the A6000 replacement with interest, but as it stands that might still leave us with limited options for good fisheye solutions - thus our current manual focus workaround with the Tokina 10-17. If a new APS-C camera's autofocus with adapters works as well as it seems to do for the A7RII then that would be interesting. Deo claims that the Saker Falcon Lite autofocus works well with the A6000's hybrid PD/CD system at least for native Canon lenses but I haven't found many relevant independent reports and none that relate to the Tokina lens, so going that route at present would be high risk.

 

At least there is now a good native macro solution for Sony E-mount owners in the 90mm FE Macro.

 

I probably won't be at the show in February but I'm speaking at the February BSOUP meeting.

 

Mark




#334303 From D80 to D7100

Posted by MarkD on 14 July 2013 - 09:12 AM

I have made the same transition, but with a D90 (unhoused), D7000 and D7100 along the way. I started with an Ikelite housing but have used Nauticam housings for the last 30 months. My thoughts:

 

Housing:

 

Ikelite housings are good value for money and do the job, but there are advantages to a modern aluminum housing that in my view justify the increased price if the budget will stretch:

  • Far superior ergonomics in use
  • Somewhat less bulky and heavy when handling and travelling
  • Most come with the now more prevalent and reliable fiberoptic connections for triggering and TTL strobe control
  • Most other housing manufacturers have improved port locking mechanisms than the less than reassuring Ike locking mechanism, especially when on the surface where so many floods happen
  • Many other housing manufacturers have easier to use and therefore safer housing back catches
  • The standard Ikelite viewfinder is in my view quite poor, but just how difficult it is to use may depend on your own eyesight. Other manufacturers make accessory magnifying viewfinders for which adapters are available for Ikelite.

 

At least one manufacturer (Nauticam) make an adapter to take Ikelite ports to make the upgrade pathway less financially painful.

 

Lenses:

 

The 60mm Micro is a great lens.

 

None of the other lenses you mention are truly wide angle under water on a DX sensor camera. They possibly come into the category of jack of all trades but master of none. The Tokina 10-17mm (fisheye) remains an excellent choice wide angle for image quality and some zoom flexibility as long as you don't mind the fisheye distortion (or straighten this up in post processing). It works well with a 100mm/4 inch mini-port which is another advantage for travelling.

 

VR is not very important at the wide-angle end of the range, especially when using strobes rather than available light. Even for macro, VR is not optimised for the sort of movement that happens underwater, and water mass/viscosity provides some mechanical dampening against the higher frequency shake for which VR is designed. However I do keep VR switched on for lenses which have it, for what it is worth.

 

Strobes:

The DS125's are first class and quite powerful strobes. However they are extremely bulky and heavy and this is compounded if you take spare proprietary battery packs and the equally bulky charger. They are not great for travel.

 

In addition, they only work with electrical trigger and Ike TTL. The former has a reputation for lower reliability and requires comparatively bulky electrical sync cords. The latter limits the flexibility of their use.

 

Inon and Sea and Sea make a range of modern strobes which are light in weight, use rechargeable AA batteries which require widely available compact fast chargers and which will trigger and provide TTL optically with a very wide range of housings and cameras.

 

Of all these things, I think it was using an accessory magnifying viewfinder that make the greatest difference in my upgrade path,

 

My two cents worth,

 

Enjoy the great D7100!

 

Regards,

 

Mark