Jump to content


  • Content Count

  • Joined

  • Last visited

  • Days Won


Everything posted by Interceptor121

  1. The 180mm port is different as it doesn’t have a flat aluminium back I think this may be the reason Sent from my iPhone using Tapatalk
  2. I own the Sony 24-70mm GM2 I have tested it for video. The lens focuses at 21 cm therefore it works perfectly with the 180mm dome I recommend a shorter extension that what Nauticam proposes for best results it sharp across the whole range The 20-70mm has a longer working distance and the lens extends a lot in addition to needing a large dome due to the working distance it will have less consistency as you zoom in from 20 to 24 because it is wider Performance of lenses behind domes depends a lot from the construction which is normally optimised for topside use so may not always be ideal underwater
  3. The small 180 port is not much smaller than the 230 The radius is 11 instead of 12 The 230 has wider field of view The tamron focuses at 19 cm from the sensor this is why it is the best rectilinear lens for emount It is also not too small so the radius required is only 10 cm to focus inside the dome Sent from my iPhone using Tapatalk
  4. You don't need to convince me I shoot most my my video in manual focus with a pull gear all my landscape and night photography and even wide angle More about the remaining hundreds of users here that say CAF with tracking is a must underwater to get a shot
  5. Sorry but this is a drop in the ocean try a few birds in flight with manual focus or car coming on a track where you want to follow it not just get a single shot
  6. Topside there are many shots you will loose with only manual focus and looking at the comments here there are people that use caf tracking for wide angle (No idea why I don't) I have used also manual focus for macro for a long time and just for moving fish portraits I use caf I think underwater requirements for auto focus are lower however topside is a totally different story unless you shoot landscape or studio you do need autofocus
  7. In reality the focal lenght is only true at infinity Macro lenses have a lot of focus breathing if they need to be small at 1:1 ratio the panasonic has become a 33mm lens while the olympus is 37mm The Olympus lens has much more focus breathing which is the reason why the lens hunts more than the Panasonic
  8. For video and 14-42 I use Subsee 5 actually unless I have tripod legs as I can't be as stable if I have too much magnification
  9. To clarify the matter of working distance The working distance is calculated from the sensor which means if a lens is very long the distance from the front element may actually be short Example Panasonic 45mm the lens is 79.4mm the working distance is 15cm from the sensor. However the working distance from the front of the lens is 65.6 mm Olympus 60mm the lens is 98.6mm the working distance is 19cm from the sensor However the working distance form the front of the lens is 87mm Which means that in practical terms the difference between the two lenses is 21.4 mm in water this is 2.8 cm It is not the case that the Olympus 60mm has significantly more working distance than the Panasonic 45mm and even in water this is less than 3cm Those 3 cm become important when you put the CMC in the mix as the wet lens is on its own a few cm thick and therefore it is easier to use with the Olympus I have used the Olympus for many years on the assumption that it would give me much more working distance and then when I finally got the Panasonic 45mm i realised the difference was minimal and I prefer the 90mm angle of view so I do no use the 60mm that much anymore unless I know I need super macro with wet lens
  10. For the 30mm? Around 2-3 cm Sent from my iPhone using Tapatalk
  11. I have 3 macro lenses for MFT 30mm panasonic 45mm Panasonic 60mm olympus The best of the three at small apertures is the 30mm which is also the fastest to focus however you are on top of things Second comes the 45mm which focuses a bit slower and really is good up to f/8 for super macro you are really close with cmc1 Last the 60mm this gives you 2-3 cm more working distance then the 45mm however this lens is best up to f/5.6 it works well with cmc1 If for supermacro you mean frame smaller than 17.3x13mm olympus 60mm is the way forward Sent from my iPhone using Tapatalk
  12. I would like to bring a different angle to the discussion While the image quality may be sufficient there is no doubt that never camera have better ergonomics and features that allow you to take your shots more easily in certain situations While years ago there were a limited number of cameras with decent autofocus or exposure aids now there are many more in almost all formats Features are more important than image quality when people upgrade a camera Sent from my iPhone using Tapatalk
  13. A bit of silicon on the threads will ensure it doesn’t get stuck Just a tiny bit is sufficient Sent from my iPhone using Tapatalk
  14. The camera before the current one last me 4 years. In between I went for a mark II upgrade because the body was the same November last year I bought into the Sony E-mount system. To be frank underwater was one of many reasons why I moved format from MFT to Full frame. To be honest some of the use cases have not improved but majority have In general terms I look at underwater gear on a 4-5 years cycle which corresponds to my camera cycle In my case I wanted something that would be an improvement on both photos and video and this was not an easy task, many cameras where better for photos, although underwater the gap is much smaller, but to have also the video part I ended up buying a Sony A1 When I read things like I have a Sony Mark IV should I get a V I think if the housing is the same why not. But I would not consider a complete change of underwater system in a 2-3 years cycle Now the elephant in the room. Based on my experience of topside and underwater photography I believe that other than close up underwater images do not resolve even 30 megapixels due to the water itself. If I was choosing a system for photography only and I was shooting underwater I would have probably bought a Sony A7 IV I also believe that requirements to shoot underwater are fairly basic compared to some other topside disciplines It is very nice to have an A1 the thing is a monster but I would have not got that one if I was shooting only underwater unless I was @Alex_Mustard and guess what he just bought one 24-32 Megapixels and good choice of lenses are adequate. Cropped sensor APSC or MFT are fine and unless you are after the ultimate quality full frame is not even required by majority of people EDIT: despite the camera may not be needing an upgrade I think that there is lot more work that can be done to optimise performance which in turn means IQ obsession but not necessarily latest gadget obsession
  15. It was a joke. You should not align a lens and light underwater Sent from my iPhone using Tapatalk
  16. That lens has a patent! Sent from my iPhone using Tapatalk
  17. Canon EF - S 35mm has a light ring around the lens
  18. The comment that metabones autofocus with 8-15mm is slow makes me think they did not set up the adapter and camera as it should be
  19. I am not sure that having infinity further away is in itself a benefit In practical terms the way it works is that I have a finite number of ports avaialble and most of them do not have a 180 degrees field of view If we look at fisheye lenses they focus very close. A dome with a small radius may contain the lens working distance Example Canon 8-15mm it focuses at 2cm from the front of the lens. A dome as small as 4 cm in radius may be sufficient however it can't physically contain the lens. So in practical terms I have 4 choices that can contain the lens field of view 1. Zen 100mm 2. Nauticam 110mm 3. Nauticam 140mm 4. Nauticam 8.5" acrylic dome All other Nauticam ports do not have 180 degrees field of view so I will ignore them. All lenses above can focus right on the surface of the dome, however as the radius goes up this means things will be further away and start looking smaller. On the other hand the infinity point will also move further away Zen 100mm infinity is 20cm from the entrance pupil Nauticam 110mm infinity is 22cm from the entrance pupil Nauticam 140mm infinity is 28cm from the entrance pupil Nauticam 8.5" infinity is 43 cm from the entrance pupil In terms of working distance Zen 100 mm I will be 16 cm from target Nauticam 110mm I will be 16.5 cm from target Nauticam 140mm I will be 18cm from target Nauticam 8.5cm I will be 21.8 cm from target In terms of infinity from the dome we have respectively Zen 100mm infinity is 15cm from the dome Nauticam 110mm infinity is 16.5cm from the dome Nauticam 140mm infinity is 21cm from the dome Nauticam 8.5" infinity is 32 cm from the dome total range of focus from focal plane (11 cm behind entrance pupil) Zen 100mm infinity is 31cm Nauticam 110mm infinity is 33 cm Nauticam 140mm infinity is 39 cm Nauticam 8.5" infinity is 54 cm I cam guarantee you that the lens is not going to become amazing when it goes from 31 to 39 cm but it may start to work in a more comfortable way when the target is 1 meter and this will never happen So going all the way to get to 54 cm infinity did not really change the world in terms of performance but it did make your rig much more bulky And this is the reason why Nauticam at the end recommends the 140mm and this is mostly because glass allows for antireflective coating not because of those 6 cm difference and at the same time if you want to get close because you want to you can One use case where a massive dome helps are split shots and that is because the depth of field required by the land section not the underwater one. Now if you go into a case where the lens can't focus inside the dome your objective is to have the biggest radius no matter what as you are wasting range due to the lens not being able to focus at all within the dome Or alternatively choose a lens that DOES focus close and is built to focus in the dome in which case one or two cm radius more are not going to make a dramatic difference Every system tends to have this lens, in MFT it was the Panasonic 8-18mm in the Sony E-Mount is the Tamron 17-28mm I do not know much about other systems but if I was planning to use them I would do the related research Those lenses tend to be not too wide, focus very close but not physically that small which means the difference between Minimum focus distance and entrance pupil is not small which means even a small radius dome won't affect the lens to focus on the glass in water The vast majority of rectilinear lenses on the market have working distance of 25-28 and are sometimes very short which means the radius of your dome to contain the working distance is 16 cm. And nobody wants to lug around a 30cm wide angle port I study all the lenses that I purchase and before taking them underwater or even investing in ports I take close distance shots on a tripod because that is what matters behind a dome. This system has given me results that i consider more than acceptable How many underwater people even shoot a wide angle or fisheye lens topside? I have spoken to many people that have never used their fisheye lens topside and have no idea of what to expect before taking the lens down...
  20. No! The whole point is that radius does not come into the equation! It is only the field of view that comes into play. This is what drives the surface that is not affected. Remember it is a % not a an absolute. Other issues are impacted by the radius but spherical aberrations is definitely one that is NOT!
  21. I agree. It is also a matter of size of this adapter or dome For example a very large dome is less subject to issues of positioning than a small one simply because the positioning error becomes smaller than the radius, the same seems to apply to the various WACPs the larger the better Majority of rectilinear wide angle lenses, but not all of them, are optimised for landscape photography and have working distance 25cm or even more this is not exactly a device that is fit for close focus wide angle for starters Fisheye lenses focus at 15cm which means few cm from the glass they are designed to get close at the outset In the end as there are limitations as you suggest, it becomes more a matter of selecting lenses that lend themselves to underwater use and then try to understand how the lens works to optimise them On the other hand you may have an amazing topside lens that is built in a way that requires a gigantic port to work properly and that is simply not designed for close range work you will be very disappointed after spending a lot of money when you try to use that lens I wish underwater users spent more time understanding the lens design and topside performance as a lot can be understood before making more investments to eventually get disappointed
  22. Hi Wolfgang The example is simply what comes from a cheap spherical lens that exhibits blurring at the edges similar to what you see in some dome port shots. You will not find literature on dome port nor any quantification of how the edge improve due to the size of the dome This research paper https://www.mdpi.com/1424-8220/16/1/48 Show that there are 3 effects of a dome port 1. Increase of depth of field as infinity is closer 2. Field of curvature 3. Spherical aberrations For the purpose of understanding the performance of a dome port I think about the optical system as a combination of the master lens and the dome with the assumption of a correct position and not considering the dome thickness If you think that way a dome is a positive meniscus lens But the reality is that the thickness does not change that much as you move to the edges so the rays do not converge all in a single point See diagram 2 here When the rays are not collimated you get spherical aberration and to minimise it you close the lens aperture. As wider lenses have more diverging rays they are more subject to spherical aberrations. The statement from wikipedia seems to indicate that the area free of aberrations is delimited by the arcsin of the ratio fo the refraction index and therefore 67% of the diameter is free of defect A spherical lens has an aplanatic point (i.e., no spherical aberration) only at a radius that equals the radius of the sphere divided by the index of refraction of the lens material. A typical value of refractive index for crown glass is 1.5 (see list), which indicates that only about 43% of the area (67% of diameter) of a spherical lens is useful.[citation needed] This would mean that a lens wider than 24mm will exhibit this issue topside When you put water index which is higher than air this angle would become 124.9 andthe surface would be 88% so although there are spherical aberration it would seem that water would reduce them not increase them Now the issue with field of curvature is also there but at the same time the dome increases depth of field which is how you fix field of curvature. Having taken shots topside and underwater of the same test target what I can say is that overall the situation does not change that much at all. In my tests at close range f/16 was needed both topside and underwater to get everything more or less in focus with both a fisheye lens and rectilinear lens I would say that in majority of cases the reason why photos taken with rectilinear lenses look ugly is because close up photos of rectilinear lenses that are very wide look ugly also topside and underwater is no different In conclusion the dome when correctly positioned and the right size (different discussion) does not appear to alter the topside performance of the lens. However as most underwater shooters are unaware of the topside performance of the lens they complain about edges that in most cases were either identically or blurred even topside
  23. The reason why this is the best solution is that it works on the field Other stuff is theoretical and nobody travels with an ultrasonic cleaner anyway Sent from my iPhone using Tapatalk
  24. The OM-1 has had many software bugs It is possible that this is just one of them missed so far Sent from my iPhone using Tapatalk
  • Create New...