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ChrisRoss

Member Since 13 Feb 2016
Online Last Active Today, 11:48 PM
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#407536 Nauticam WWL-1 on different setups

Posted by ChrisRoss on Today, 05:37 PM

 

EZ. Check.
Yes I know, the 12-50 has a rather expensive port + zoom gear. I haven't started adding prices yet, but of course it matters.

 

 

No, I would definitely want the float collar. I'll check the pockets I have, but I suspect you're right. They are quite roomy (Hollis thigh pocket, https://www.hollis.c...n-thigh-pocket/) but the whole WWL-1 with collar sounds optimistic.

The WWL is definitely a great option for wide angle stuff, no question about optical quality, I think the idea of taking it off mid dive and playing macro is where the questions lie, it weighs 160gr underwater with buoyancy collar, so your rig is suddenly 160 gr lighter when you remove it - if you put it on an arm on the rig that problem goes away, but if you put it in a pocket, then your rig is suddenly lighter which means you need to have the rig at least 160 gr negative if you want to remove it.   A slightly positive rig can be painful particularly for macro, I dived with a rig that I would guess was <100gr positive once and it was difficult to use for close work.  There's a whole thread on what to do with a WWL on the video forum here on wetpixel right now.

 

On the topic of Low ISO, in theory yes you lose some range when using the low ISO option, but is that something you really need underwater?  Maybe for sun balls but the differences as measured by DXO are almost trivial.  By way of example I found this post:  http://wetpixel.com/forums/index.php?showtopic=64240#entry407528 with photos taken with a Canon D80 which is about average between the Sony and the Olympus in performance:  https://www.dxomark.com/Cameras/Compare/Side-by-side/Canon-EOS-80D-versus-Olympus-OM-D-E-M1-Mark-II-versus-Sony-A6400___1076_1136_1281  to me the performance on the sun balls is pretty damn good and I believe the Olympus should be able to do something quite similar.  T

 

For me at any rate I would use other criteria than sensor performance as a selection criteria for example the Olympus has a 1720 mAhr battery while the Sony has a 1080 mAhr battery they may consume at different rates of course, the CIPA ratings are 360 shots for the A6400 and 440 for the Olympus.  The A6400 is reported to be much improved over the A6300/6500 but looks like it still falls well short of the olympus performance for number of shots. The lens selection from Panasonic and Olympus is also much better, including two native fisheyes to choose from.  As you mention flash sync is limited to 1/160 and also no manual option.  The little accessory flash that comes with olympus can be set at 1/64 power on manual to trigger strobes preserving battery power and it reliably triggers my INON Z-240s.




#407500 Nauticam WWL-1 on different setups

Posted by ChrisRoss on Today, 05:50 AM

The EM-1 MkII is a great little camera and has a huge range of lens options, AF is quite snappy, I use C-AF plus tracking as my default for both wide angle and macro.  Battery is good for at least 3 dives with some juice still left.   I had a look at the plots compared to the Sony and the differences really are quite small, I note that the EM-1 MkII can also use ISO Low which is about ISO64, they show this on the noise performance plot but not the dynamic range plot.   I'm not sure what benefit you see from the Sony going to ISO 100.

 

I use the EM-1 II with the 30 & 60mm macros, the 12-40mm f2.8 and the 8mm fisheye.  The 12-40 in particular is a nice lens getting down to 0.3x magnification, I use it for temperate water diving around Sydney.  I also have the little panasonic fisheye and ZEN 100mm port for it and it produces nice results from a compact package.

 

The 14-42 while giving 80mm equivalent focal length without the WWL gives a max magnification of 0.23x so would probably benefit from a wet lens for smaller stuff.  In theory the 12-50 is better in this regard but without the special dedicated port to allowing throwing the macro switch it only gets similar magnification to the 14-42. 

 

The other issue you come up against is what to do with the WWL if you take it off, even with the flotation collar it weights 160gr UW, so ideally you want to place it on an arm in a dock , but it's sizable (130mm dia) and could limit your ability to put your strobes in your preferred position.      I don't know what type of diver you are, me I would take the capability UW but could easily see not using it with the need to remove it, not drop it and dock it.    An alternative might be the MWL-1 lens which provides a 150° field with a 30mm macro lens on the olympus.  The little Panasonic 30mm f2.8 macro lens is very snappy and great for fish portraits and small stuff down to about 0.5x or maybe 20-30mm long - you wouldn't need (and can't use) a wet macro lens with it and Nauticam have flip holder making it much more convenient to flip in and out. 

 

This fish is about 200mm long and shot with 30mm macro - total grab shot as they normally hide in kelp:  http://www.aus-natur...r Wrasse 3.html

This is about a 90mm long nudi shot with the 30mm: 




#407448 Strobe Flood Damage Hot Gas and the Pressure Relief Valve, Fact or Fiction?

Posted by ChrisRoss on 23 June 2019 - 05:38 PM

As I pointed out in the link above:  https://www.scubaboard.com/community/threads/flooded-inon-urgent.356273/.%C2%A0 this link has Reef photo an authorized INON service facility saying that there are o-rings sealing off the electrodes.  I also reported in another post about p50 of the INON basic instruction manual which recommends changing all o-rings every 3 years.  You will also note Reef's recommendation to put your strobe in to be checked if you ever flood the battery compartment.  I recall various threads here asking about the waterproofs-ness of INON's battery compartment and the responses are mixed some relating stories where they survived a flood and others where it has leaked.  To me this indicates the strobes are sealed - but eventually that seal will fail due to aging of the o-rings.


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#407435 Nauticam D850 TTL Converter Stinks

Posted by ChrisRoss on 23 June 2019 - 04:17 AM

Yes, I know all that but the camera has to work out the correct exposure and the TTL sytem has to interpret that exposure and convey it to the strobes and if you were going to ask for it  to be fixed would likely need to go through some steps to show all that is in order.   Logically you would think if anything that this one might over expose trying to compensate for the black BG.   

 

Assume you have double checked the mode dial is set to your external flash type on the TTL board?  Interestingly enough the manual states that you shouldn't expect it to work in air!  The other thing I would check if you haven't done so already is to see if the system responds at all to flash exp compensation if it doesn't it may point to a synchronization problem.   It appears you can only dial in one step of + compensation from the camera so maybe you could dial in +  comp on camera and strobe and see if it is noticeably brighter than zero compensation.




#407153 Olympus PT-EP13 Underwater Housing issues and cleaning

Posted by ChrisRoss on 14 June 2019 - 07:44 PM

The EM-1 MkII is excellent - great AF, significantly better than the EM-5 MkII.  C-AF plus tracking actually works well and is my default AF option underwater for both wide and macro.  Sensor wise you have a few more MP but performance is not a huge leap above the EM-5 II, certainly noticeable but not a big step forward.




#407117 Beginner question: Mininum focusing distance

Posted by ChrisRoss on 13 June 2019 - 11:51 PM

What I find can happen with the contrast detect AF systems is they "look through" the subject to focus on what is behind if it has more contrast than the subject or if the subject is a little small.  Generally though I look for two things focus acquisition and the subject becoming more defined or snapping to focus.  The minimum focus distance is measured from the sensor plane and as stated above you are focusing on a virtual image, which is closer.  You can use this to Visualise  how far away you can focus:  https://oceanity.com.au/tools/virtual-image-calculator/ 

 

For a 6 inch dome (with a 3" radius of curvature ) at 20cm object distance from dome the virtual image is 8.1cm from the dome, which is as low as the calculator goes.  I would estimate the virtual image is 5cm from the dome with an object 10cm from the dome and it really should be able to focus on that.  If you were focusing on coral maybe the back of the coral head with coral branches against clear water had the better contrast and it focused there.  Just because it locked focus does not mean it focused on what you wanted to focus on.

 

Based on my Oly 12-40 which has the same more or less min focus distance you should be able to focus maybe 5cm from the port surface.  You could try assigning focus peaking to a function button and confirm it's peaking around the thing you want to focus upon?




#406773 ikelite 6" dome + old canon lens = no focus

Posted by ChrisRoss on 03 June 2019 - 08:32 PM

You could make it work with a diopter, the minimum focusing distance is 40cm so it can't focus on the dome virtual image, which will be about 20.8 cm from the dome surface for an object at infinity and probably around 14cm from the dome at 0.5m object distance.  The object distance is measured from the sensor when talking about minimum focus distance.  This assumes the dome is a 6" hemisphere.  If you don't understand dome port optics, the short explanation is that due to the being in water the lens does not focus on the object itself but on a virtual image of the object which is very close to the dome.  SO lenses have to focus down to around 30cm to be usable without a diopter with this dome.  Larger domes have the virtual image further away so more lenses are compatible

 

Looking at the ikelite port chart, the 35-80 lens is listed as requiring a +4 diopter with an 8" dome, so that might be a good starting point.  You can test the diopter by checking that it focuses on objects between 14 cm and 21 cm from the dome surface on land.  If you look at the ikelite website is says here: https://www.ikelite....-up-to-4-inches  that :"  Zoom lenses that do not focus to 12 inches (30 cm) require a +4 diopter close-up lens."

 

A flat port doesn't allow you to go very wide and will degrade images a little at the edges more so as you go wider.   The 35-70 would be equivalent to about a 45-90mm lens through a flat port due to the magnifying effect that a flat port has. 

 

There's nothing magic about lenses listed, they are just the ones that ikelite has tested.  if they only focus down to 40cm, just add a diopter.  The other requirement is not to be more than 100mm long according to Ikelite website. If they meet those criteria, you could try them.    The other issue is whether you can find zoom gears for the lenses.

 

I don't know what you are planning on shooting with the 35-70, it's not very wide and doesn't focus very close so even with the diopter macro is difficult, and a bit narrow for scenic.   I would suggest a 24-85 might be more generally useful and would do all the 35-70 does plus being able to shoot wider for scenic, fish schools etc.  It would probably be available quite cheaply second hand.    I would guess the 35-70 may work well for fish portraits.  It all depends on what you planning on shooting with it.




#406517 Olympus 8mm Fisheye with larger dome via N85 - N120 converter

Posted by ChrisRoss on 23 May 2019 - 08:54 PM

ChrisRoss, extremely clear explanation. Actually I got a used PTEP14 so Im planning to get my EM1 Mark II underwater and expand a little bit my options. I have been shooting mostly Fisheye and Macro for the last 3 years and start feeling a bit limited with the Fish Eye.

I am thinking that with a 170mm+ dome in the PTEP14, I can fit both the Olympus 7-14 as well as the 12-40 (I would love to have the versatility of the 12-40 with zoom gear...).

There are still a couple of the aspects where Ive found little info. One is regarding performance of 12-40 in higher focal lengths behind a dome. The other one is regarding semi-domes performance, as AoI officially recommends a semi-dome for the 12-40.

Thanks again for the very relevant input.

Sent from my SM-N960F using Tapatalk
ChrisRoss, extremely clear explanation. Actually I got a used PTEP14 so Im planning to get my EM1 Mark II underwater and expand a little bit my options. I have been shooting mostly Fisheye and Macro for the last 3 years and start feeling a bit limited with the Fish Eye.

I am thinking that with a 170mm+ dome in the PTEP14, I can fit both the Olympus 7-14 as well as the 12-40 (I would love to have the versatility of the 12-40 with zoom gear...).

There are still a couple of the aspects where Ive found little info. One is regarding performance of 12-40 in higher focal lengths behind a dome. The other one is regarding semi-domes performance, as AoI officially recommends a semi-dome for the 12-40.

Thanks again for the very relevant input.

Sent from my SM-N960F using Tapatalk

The EM-1 II is great UW, AF is a big improvement over the EM-5 II, C-AF plus tracking works very well.  The 12-40 is very good at all focal lengths some examples:

 

http://homepages.ihug.com.au/~chrisx2/images/GiantCuttlefish20.jpg taken at 12mm

 

http://homepages.ihug.com.au/~chrisx2/images/Wobbegong4.jpg taken at 40mm both near full frame just a slight crop for composition.  I use it behind the Zen 170mm dome

 

http://homepages.ihu...lackEyeGoby.jpg  this is very close at 40mm

 

There are a number of dome options for the PT-EP14 including Olympus's own dome, this is the system chart:  https://asia.olympus...t/000085635.pdf




#406413 Online critter ID

Posted by ChrisRoss on 20 May 2019 - 03:32 PM

I use this a bit:

 

http://skaphandrus.c...-identification

 

if you contribute photos you get points to unlock some of the groups, others like nudis are free.  The nudi key is successful maybe 50% of the time.




#406295 Diopter for WA?

Posted by ChrisRoss on 15 May 2019 - 01:27 AM

You don't need a diopter for this lens,  as it focuses close enough by itself.  A diopter is used for WA if the lens can't focus close enough to focus on the virtual image formed by the dome which is about 3 dome radii away from the dome surface.  If the lens can already focus on this a diopter does not help.

 

The S&S lens helps by bringing the corners into focus, the virtual image is curved and the corners are closer and you need to stop down to bring them into focus.  The S&S lens helps by partly correcting this curved image so you dont need to stop down as much to bring the corners into focus.




#406134 Strobe Failure A note of caution

Posted by ChrisRoss on 08 May 2019 - 10:46 PM

Still air is actually quite a good insulator, and most insulating materials work by trapping small pockets of still air- just look at double glazing - the insulation comes from trapping air between the panes.  Plastic has significantly lower conductivity than metal which is why pots and pans often have plastic handles, you can pick them up without protection on the stove.  INON now has a heat sink onto which all of the heat producing components are attached and that extends to the outside to conduct heat to the water.  Retra makes their housing from aluminium to assist with shedding heat, so these manufacturers are attempting do something about the heat problem.  INON Z-330 heat sink is described here:  https://www.backscat...derwater-Strobe

 

I suspect that the ring shaped tubes are significantly more expensive so they use off the shelf straight tubes to build to a price.  The ring flash also has more surface area so probably runs cooler than the straight tubes.




#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,