Jump to content


ChrisRoss

Member Since 13 Feb 2016
Offline Last Active Today, 05:03 AM
-----

#405617 Durability of Nauticam handles

Posted by ChrisRoss on 21 April 2019 - 03:02 PM

I've found my Nauticam flextray quite solid.  You do need to pay attention to periodically tighten the screws and use the stainless brackets between the top of the housing and top of the tray handle, which significantly strengthens the whole setup.   I also grease all of my screws to help guard against corrosion. 




#405146 Importance of auto-off on focus light?

Posted by ChrisRoss on 10 April 2019 - 09:48 AM

If you have the capability use back button focus, you can normally assign that to one of the function buttons, then you have the best of both worlds.  Use the function button to focus then don't touch it again till you need to.  That way if you find a subject that's really close you can focus on it if need be.




#405069 Importance of auto-off on focus light?

Posted by ChrisRoss on 08 April 2019 - 07:57 AM

certainly there are situations where you could make use of the focus light when shooting macro, however the OP specifically mentions CFWA where it may present some issues .

 

I'm also sure you could get the focus light to show if for some reason you shot high ISO and/or wide aperture, but that's not a normal situation in UW photography where the strobes are set to overpower ambient light.  It could be an issue  for example shooting a small sensor compact at f2 (quite common in such cameras like theTG5), but on a m43 I would think you'd mostly shoot around f8 at least if behind a dome port.

 

The explanation as to how the light is able to switch off is that the duration of the strobe exposure is much shorter than the shutter speed which sets the ambient light exposure.  So if the light turns off for say1/8 of a second after receiving the signal to shut down, likely the light is only present for something around the duration of the strobe exposure, so a very short time compared to the total time the shutter is open.




#405052 Importance of auto-off on focus light?

Posted by ChrisRoss on 07 April 2019 - 06:05 PM

The "focus" light on your strobe is of little use as it has a narrow beam and one of the first rules of UW photography is don't point your strobe at your subject.    Your focus light does not need to be very bright at all, I find a 350 lumen INON UW torch does a good job and with that low power level it's quite a few stops under you main exposure s just does not show up in the image.  I have used such a ight mounted to the cold shoe with both the EM-5 Mkii and EM-1 MkII and it just works,




#404792 Sony RX100 VA - Nauticam package

Posted by ChrisRoss on 29 March 2019 - 11:11 PM

The shutter release does make things easier.  Definitely get the the vacuum valve/pump, gives great peace of mind!  It should be a good little package.

 

Did you see this article:  https://www.backscatter.com/reviews/post/Backscatter-Best-Underwater-Compact-Cameras 

 

The Nauticam housing with tray is the same price for both the LX10 and RX100VA so they might allow the same package for the LX10 as the RX100VA - wouldn't hurt to ask if it was of interest.  Note the link you provided states ships to the Americas and the Caribbean, and you don't appear to be located there.




#404743 Strobe Advice

Posted by ChrisRoss on 27 March 2019 - 09:48 PM

The figures are fairly straight forward for strobe power, the Z-330 is GN 33 and the D200 GN 20.  This is about 1 1/3 stop difference in output at full power  They both have a 110° field without diffusers. 

 

The YS-D2 is GN 32 - very close to the Z-330 you might think, but it has an 80° beam so its not apples to apples.  With the 100° diffuser it reduces to GN 24 and the 120° difffuser is GN 20. 

 

If you add the bundled diffuser to the Z330 you lose 1/3 stop so it's about GN 26.  So more power and a wider beam than the YS-D2 with 100° diffuser.

 

The INONs seem to have a very good reputation for reliability, I have been using my Z-240s for about 3 years now with no problems.  The manual is totally confusing, but a plain english guide is here:  https://reefphoto.co...-inon-strobes-1

 

The D200 is very new so probably not much data available, I would suggest putting your name down for a Z-330




#404654 Shiprock, Sydney Australia

Posted by ChrisRoss on 24 March 2019 - 07:49 PM

One of the best regarded divesites in Sydney is Shiprock.  The site is on Port Hacking to the south of Sydney and the entrance is in suburbia, surrounded by expensive waterfront homes, it has an amazing array of life and being an aquatic reserve  fish are plentiful.  This is a shore dive and there are steep steps down a cliff face to reach the entry point and the site features a wall running from about 7 to 15m deep.  It is subject to strong tidal currents and needs to be dived on a slack preferably high tide.  Here is a google maps link:  https://goo.gl/maps/Nq2mRe95rYu

 

Had a really nice dive there last Friday and here's some pics, descriptions below the pic  All taken with OM-D EM-1 MkII and Panasonic 30mm macro - Nauticam housing, INON Z-240 strobes:

 

PineappleFish3.jpg

Pineapple fish are nocturnal and have a light producing organ that assists with their hunting.  Shiprock is one of the few spots they are regularly found around Sydney dive sites.

 

SeivePatternedMoray2.jpg

Sieve Patterned Moray, less common than the regularly seen Green Moray

 

RingscaleTripleFin2.jpg

Ringscale Triple Fin, a small fish that claims sections of rock as territory, common at Shiprock but not so common elsewhere,

 

SixSpineLeatherjacket4.jpg

Six Spine Leatherjacket, quite common of many dive sites, but tend to be skittish, this one is about 300mm long so a bit of a challenge for a macro lens

 

PygmyLeatherjacket5.jpg

A Pygmy Leatherjacket another common fish around Sydney they seem to have their tail curled around semi permanently

 

EasternFrogfish.jpg

Eastern Frogfish, an ambush predator hiding under one of the many ledges at Shiprock

 

Doriprismatica_atromarginata6.jpg

Doroprismatica atromarginata, quite common around Sydney and the only Nudi I found this dive,  At other times the variety of nudis is much greater.

 

BlotchedHawkfish2.jpg

Blotched Hawkfish, Shiprock is the only Sydney dive site I see these regularly




#404624 Smaller alternative to Nikon FX (m4/3)

Posted by ChrisRoss on 23 March 2019 - 06:22 PM


 

There is a misconception about how WWL and WACP work:

 

 

Conversion lenses offer a virtual image that is parallel to the sensor, so remove the DOF issue that is a problem with dome/lens combinations. The WACP can be used with high-resolution cameras at very open apertures (f/4) and still give excellent corner results. 

 

There's not really any misconception, I'm fully aware of how the WACP functions - it's basically a field flattener, bringing the corners of the curved virtual image into focus at the same time expanding the field of view, probably not so good with choice of words.  I recalled reading the reviews of the WACP and WWL  and was not sure exactly how low you could go with aperture and seemed to recall f8 being touted as a limit.   Since posting that I went and reviewed the article in UWP 99 to confirm my recollections.    The UWP 99 can be found here:  http://www.uwpmag.com/?download=99  

 

On p42 you can see peak image quality in the corners occurs at f16 for the chosen rectilinear (nikon 14-28) as does the WACP albeit at higher resolution and the WACP resolution drops with aperture and is equal to the 14-28 at f16 when the WACP is at f8, basically a 2 stop advantage. f 5.6 is certainly usable.  So aperture does impact corner quality still, whether this is a limitation of the WACP/WWL or the kit lens being used is less certain.

 

The main purpose of the post was to explore any aperture advantage that might be obtained in m43 over full frame.  On p42 you'll also see data for the WWL vs the Oly 7-14mm,  The 7-14 peaks at f11 and the WWL is equal or better than the 7-14 down to f5.6 and again there's a 2-stop advantage.  

 

The whole idea behind the sort of comparison is that when people see the dynamic range, noise and other  numbers in isolation the numbers quoted are the numbers for base ISO, but the Noise, DR and colour depth all reduce as ISO goes up.  If you can operate 2 stops wider open you can use two stops better ISO on m43  and claw back part of the full frame advantage.  However is you can get to f5.6 to f4 of full frame that advantage is very much reduced to non-existent as the lenses being used will be wide open.   It's still not as good as full frame but if you are aware and adjust your aperture and ISO appropriately it closes the gap.  Of course is you shoot your full frame at base ISO it leaps ahead. 

 

It will be interesting to follow developments in water contact optics, the WACP certainly provides excellent performance at a price in both purchase $$ and weight.   Maybe a hybrid between the Sea and Sea internal corrector and a water contact optic? 




#404599 Nauticam GH5 your port and lens. Why?

Posted by ChrisRoss on 22 March 2019 - 06:05 PM

This post may be relevant:  http://wetpixel.com/forums/index.php?showtopic=63783 in here Phil Rudin states that the corners are much better using the Zen 200mm dome compared to the 170/180mm domes, though unfortunately that dome appears to be discontinued.  This seems plausible to me as one day i trilalled my Panasonic 7-14 to find the entrance pupil location and as far as I can figure it appears to be 20-25mm forward of the optimal position when using the Zen DP-170 typeII.  A further check with a little trigonometry revealed it was positioned forward to prevent vignetting in the 170mm dome.  This is relatively easy to check.... the radius of curvature of the Zen DP-170 is 110mm , 110mm measured from the dome is 15mm from the port bayonet end and there is no way the entrance pupil is that far back.

 

If you do more trig , you can calculate the height of the sphere segment for the 170mm dome and the 200mm dome, which both have a 110mm radius of curvature and you will calculate h=40mm for the 170mm dome and h=64mm for the 200mm dome, so with the same extension the 200mm dome is 24mm further forward from the lens which should place the entrance pupil just about right on the radius of curvature of the dome, which would  explain better corners with the 200mm dome.  Both domes are the same radius, however so the virtual image is the same radius, but it is further away by the difference in dome segment height making it easier to focus upon.  This is for the ZEN 170 vs the 200mm dome, seems you have the Nauticam 180mm dome which may be slightly different and the location of the entrance pupil for the Oly 7-14 will be different and you would have to calculate that for your self, but I doubt the entrance pupil is way at the back of the lens. 

 

It seems manufacturers pick a compromise between vignetting and positioning of the entrance pupil, probably on the basis corners are good enough and the situation rapidly improves once you zoom a little as you are no longer trying to get the very far edges of the virtual image in focus.  This seems essential on the partial hemisphere domes in the 170-180mm size range as you need to push the lens far enough forward to see over the edge of the dome.  As to the original problem you may find the corners improve by zooming in to 8-9mm or so and reserving 7-8mm for blue water subjects where the corners are water?

 

On the 60mm macro lens, the dial is there to help with AF keeping it within a certain range.  The 1:1 setting is spring loaded and you use it to send the lens to 1:1 focus and have AF take over from there.  MF is really not practical due to the gearing on the focus dial being so high, you really need multiple spins on the housing focus knob to see any change at all in focus.  The only approach is AF on back button focus then use a Fn button to activate zebras and rock back and forth to get/hold focus, DOF is very shallow at 1:1 so absolute steadiness in needed to keep focus where you want it and any sort of surge complicates matters more as there's no way to keep up with it.  This tends to mean you need to back off for a wider view and greater DOF.  I ended up buying the 30mm macro as most subjects I shoot require 1:2 or less magnification - nothing magical about 1:1 just use the magnification needed to frame your critter.  To explain the 30mm macro will do 1:1 but the subject is too close to the port, maybe 10-20mm from the glass.  I'll swap back and forth depending on the dive site and what I expect to find.   Keep in mind I shoot stills so just need to squeeze the shutter at the right moment, video needs to keep the subject framed for many seconds without losing focus making it even more challenging. 

 

I'm not sure what you are shooting in the way of macro, if it's not super small the 30mm may be easier to handle and certainly snaps to focus better on my EM-1 MkII.  I have the Panasonic 30mm macro.




#404577 Smaller alternative to Nikon FX (m4/3)

Posted by ChrisRoss on 22 March 2019 - 02:04 AM

Carry-on ability has a lot to do with where you fly to and from, my  experience having flown in the USA is it's a bit of a free for all there and you need to be in the early boarding groups to find overhead space, but if you are no problem bringing big things and the kitchen sink on board, in other markets budget carriers will weigh carry-ons with a 7kg weight limit so they can charge you to check it.  It yet other markets they apply carry-on rules with an iron fist because "Those are the rules!!!"     I know they look similar in the photo but when you see them in person the big DSLR housing look really bulky.    I fully agree though, don't start with "this is the best camera - what does it take to get it underwater?"  but look at the total system. 




#404532 Classified Forum Abuses and Policies

Posted by ChrisRoss on 20 March 2019 - 11:51 PM

I would think there is also an issue with Privacy laws, I'm not entirely familiar with the details of privacy law in different countries, but we do undergo privacy training at work (a US based multinational company)  and it's a definite no-no to release personal information about another party which would include things such as their full name address and phone number.  How do the admins know for example that the complainant won't start stalking the other party?  I'm not saying for a second this is the case, but the admins just don't know and would create an additional burden of the admins if they were to release information.  Of course the way around this would be a subpoena requiring release of information

 

I would think WP would risk legal exposure if they released those details and are right to withhold.  Not least because they would need to adjudicate on the dispute which is what they are trying to avoid.   The Classifieds forum is quite a useful service and if the admins keep getting dragged into disputes this it may place the forum at risk.




#404530 Smaller alternative to Nikon FX (m4/3)

Posted by ChrisRoss on 20 March 2019 - 03:05 PM

If you are concerned at all about weight and travelling then m43 is certainly an advantage.  This is my full kit packed into a carry on size backpack:

 

IMG_2948.jpg

 

Top row L-R Zen 100mm dome for 8mm,  Panasonic 8mm fisheye, Oly 60mm macro, Oly 12-40, Pany 7-14.  Middle row:  n65 macro port, 2 x Z-240, Zen 170mm dome.  Bottom row, NA-EM1 housing - camera is in housing, spare batteries etc.  The backpack is a Think Tank Street walker Hard drive, carry on legal size and has a laptop pouch under.  I even fitted it into the overhead locker on a Garuda CRJ commuter jet in Indonesia.    Your proposed m43 kit would fit with room to spare for a change of underwear and other essentials - weight is probably around 10kg.  Certainly can't get close to that with a full frame kit except perhaps for a pure macro kit.  To me m43 was a sweet spot on cost/size/performance.




#404349 troubles with subtronic underwater flashes

Posted by ChrisRoss on 15 March 2019 - 10:02 PM

You are saying you are using them in manual mode but are using a 1 pre-flash mode on the strobe.  What are you doing on camera, it seems that if you are using a single preflash mode on the subtronic the camera must also be providing that pre flash and the main flash in order synchronise?  It seems like the strobe is flashing twice and does not recycle quickly enough to provide a second flash in quick succession at higher powers but at lower powers it has enough in reserve to provide the second flash - at least from the description provided.

 

The EM-1 can use manual flash which does not have a pre flash.  Have you tried setting the camera to manual flash at low power and the subtronic flash to zero pre flash?




#404280 New to UW photography - looking for something particular

Posted by ChrisRoss on 13 March 2019 - 10:54 PM

There are some basic things in your notes that are not correct.

 

First the 10-18mm f4 is not a fisheye lens, it's a rectilinear and is equivalent to 15-27mm lens on a full frame and has a field of view of 110°-75° across the diagonal.  A fisheye provides a 180° angle of view across the frame.

 

the 16-35 will be 24- 52mm equivalent.  (84° - 46°) which is getting a little narrow for underwater. 

 

The 28mm f2 on the A6000 would be equivalent to 42mm and if you have it in a flat port it would be more like a 55mm lens as a flat port will magnify the image about 1.3x.   That's a 42° angle of view with the flat port which is way too narrow.

 

On the Salted line housing do your homework, the early models had no ability to zoom, the newer models provide zoom, but not for every lens.   A lot of people love them on this forum, but personally I think you get what you pay for and I'd rather pay more for a housing to get features like zoom gears for a wide range of lenses and proper extension for the domes etc.  You could look at Fantasea or perhaps Ikelite or look in the classifieds.  Fanatsea have a full range of ports and gears to suit most lenses you would want to use.

 

Based on what you want to do, I believe you are  in wide angle territory and will need a dome.  This means you MUST stop down or the corners will be mushy , more so at the widest settings.  Even though the water is clear it still absorbs light and colour and if you decide you want strobes you still must be very close!   If you are shooting into the light - i.e. the light beams you'll be recording something more akin to silhouettes without strobes unless you place your model in the beam and the light will be coming from above, not much from the side unless you have light from another opening coming over your shoulder- if that's what you want fine, just understand your limitations.   You can use flat ports but again corner quality will be an issue and you can only go so wide with a flat port before the light rays just do not enter the port.  I would suggest surfing round the internet to see what other people are using in the way of lenses, for the type of shot you want to do.

 

It seems to me I would want to use a fisheye and a native fisheye lens at that which means something other Sony. Maybe a m43 camera with the panasonic fisheye lens?, the cheapest option is likely to be a 1" sensor compact with a wet wide lens or again look in the classifieds to see what is on offer if budget is a concern.  Look at the overall system, not just "this is a good camera so I want use it UW."

 

It also seems like corner quality is less important if the corners are black cave, which relaxes your  needs a little - you can open the aperture a bit more, but I'm talking f8, maybe f5.6, definitely not f2 and maybe get away with smaller domes. 

 

I would want a vacuum system regardless of what type of diving I was doing!




#404231 A7SIII, Lens/port recommendations

Posted by ChrisRoss on 12 March 2019 - 10:06 PM

I've been in those forests many years ago and they were very dark as I recall, a difficult problem, with probably no good solutions, though I think strobes would help a lot, but may cause additional difficulties around log jams.  Seems like the usual solutions for marine shooting are really not all that applicable and you have competing demands.  You need fast shutter speeds so you want to open up the aperture but the corners will be a problem.  You want a smaller dome for carrying and use in shallow streams but that makes the corners worse and you need to stop down more.   You could just crop the corners out but you lose the benefit of the full frame high ISO performance progressively as you remove pixels. I would also suggest you enquire about AF performance in very low light.

 

Regarding your lens choice, my gut feel is that a fisheye is probably not the solution, you would need to be 150mm from a 400mm fish to fill the frame and the field of view at 1m distance is about 4m wide.  So that leaves you with a rectilinear with dome or WACP.  The WACP for the Sony with 28-70 lens gives you a 10-25mm equivalent lens, which at the 25mm end a 300mm fish filling frame from edge to edge you are about 200mm away from the port or so.  If you're going to 300mm - 1.3m away from a fish (I'm guessing is 300-600mm long??)  it seems to me like a 24-70 f4 lens might be a better choice and a 180mm dome port would be a good fit.

 

It seems like a specialized field, have PM'd Tom Kline?  he shoots salmon in Alaska and may be able to make some recommendations on the lens class that works best for him?