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Everything posted by Chris Ross
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You could test 45mm extension for vignetting alone on land opening the housing back and pulling the camera back 5mm. It proves Massimo's statement that 16mm is the widest the 180mm dome accommodates and you need to put the EP ahead the centre of curvature to avoid vignetting at shorter focal lengths
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Photo Editing Software Suggestions
Chris Ross replied to brightnight's topic in Shooting Technique, Workflow and Editing
there are other buy once options around. I use use Capture One Pro and like the way it works, you can do a lot of work prior to it doing the RAW conversion for you. I like I can adjust levels there- to me its the most intuitive tool to do black/white points and colour balance. Seems to me it could replace Lightroom quite readily, though the learning curve can be steep. You can also try Affinity photo, it's a one off price and cheap enough to just try it out, they had a sale a while back and I picked it up for $50. I tried it out, a bit different to Photoshop but quite capable. I never liked the proprietary catalogue system of Lightroom and was never tempted to try it out and never a fan of the subscription model, I still use CS6 for final finishing work, but getting it to activate on Win 11 is a challenge I haven't overcome on my new laptop. -
Backscatter MF-2 in HSS mode
Chris Ross replied to hedonist222's topic in Lights, Strobes, and Lighting Technique
HSS is often setup from the camera menus as the camera is the thing that needs to change sync timing. It should be in the same place where you would select HSS with a land based flash. -
Thanks for the update, I couldn't find it anywhere on line, it's not on the extension port data pdf and no photos or specs on the websites.
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The 48461 should be about 10mm longer than the 48462 so about a 49-50mm extension. This is based upon the difference in recommended extensions between the acrylic and glass port
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Mexico Underwater Camera "Tax" spread to Cancun
Chris Ross replied to ShallowSeasGallery's topic in Trip Reports & Travel
In theory this could happen in almost any country, importing things beyond the duty free limits attracts at least GST/VAT the way the laws are written, it's just that someone in Mexico has decided to make a name for themself by rigorously applying the rules - of course assuming the charges go into customs revenue! I see that the Reddit thread mentions that the charges on their card statement didn't seem like an official Government dept so quite likely scamming. If you read the fine print it could be applied in many places and being used or not generally doesn't change things. Again in theory if you have a mega expensive rig you could get a carnet which provides assurance you will re-export the items in question. It's expensive paperwork though. If you have been stung it also should work that you can request a receipt with your items listed including serial numbers so that if you come back you pay the tax only once. Whether this works in practice who knows, but requesting an itemised receipt seems like it is worth doing if you think you may come back at some time. However if it is scamming then they will no doubt find some hole in your evidence and charge you anyway. Of course it discourages tourists and as word gets around will impact revenues but likely the customs department is not concerned as the lack of tourists is another departments problem. -
Thanks for the analysis, I think from what Massimo published previously the max field from the centre of curvature is about equivalent to a 14mm rectilinear lens so the 10mm would need to sit forward of the centre of curvature if is not to vignette. You could probably test adding 5mm extension for vignetting by sliding the camera back on it's mounting plate while sitting in the housing.
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Seems odd they are talking about making it with no shades - there's no mention of having to remove the shades with a full frame fisheye lens. No extension also doesn't sound right, presumably it must have some built in extension. If you compare the 10mm laowa lens to to the Canon 8-15 with Metabones - both should have the entrance pupil right up front, so the difference in length between the two should be close to the difference in extension requirements. The difference is (83+24) - 73mm = 34 mm The Canon 8-15 takes a 48462 39.5mm extension with the glass dome while it takes the a 48461 with the acrylic dome. The 48461 extension dimension seems to be a state secret, I can't find it! but looking at the port chart the acrylic requires approx 10mm more extension so assume the extension needed is 49.5mm. This gives an an extension of 49.5 - 34 = 15.5mm so very close to the 16.5mm ring and the lens would likely be too far forward to use without extension - just the dome. Seems like it would be worth checking with a 48456 - 16.5mm extension to see if it vignettes. Keep in mind this is a ball park estimate that indicates it's worth trying and it seems to indicate the 20mm might be too long. It also tends to confirm why Aquatica are working on a dedicated dome.
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How do you pack your dive gear for travel?
Chris Ross replied to Troporobo's topic in Travel Gear and Packing Tips
I'm using a Beuchat dive bag at the moment - it's OK, does the job, but the hardware is getting rusty and looking generally beat up. The answer I think depends on whether you are likely to have to pack away wet gear on the return trip. The zippers on the dive bag are still good, but I used another standard carry on bag for my dive camera, including hauling onto dive boats where it was exposed to salt water. Those zippers are in poor shape and have seized up a couple of times and the zips on the outside pockets are totally stuck. So that may be a risk for standard luggage used to haul wet dive gear. On the topic of wheels, I prefer the 2 wheel versions, the 4 wheel bags are nice strolling through the airport, but get onto uneven terrain like the footpaths in many Asian cities and the 2 wheel bags are easier to handle, the wheels are also better protected than the spinner wheels. I'm looking at the Stahlsac bags for my next dive bag seem to get OK reviews, though they are 5 and 6 kg empty. -
Nauticam Macro Port Glass Replacement
Chris Ross replied to johnvila's topic in Photography Gear and Technique
I finally came across this post: https://wetpixel.com/forums/index.php?/topic/68709-domeflat-port-deconstruction/&do=findComment&comment=434535 which outlines the process. -
Another option I have seen local divers using and which they swear by is this item, saw it the other day at my local dive shop: https://divediversions.com/products/divevue-mount-glasses-to-your-dive-mask The advantage is you can readily change prescriptions and pull them in and out of the field of vision. Primarily designed for use with cheap readers you could use any prescription you need in an appropriate set of frames. You need a go-pro mount on your mask to attach this clamp to.
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Nauticam Macro Port Glass Replacement
Chris Ross replied to johnvila's topic in Photography Gear and Technique
There was a post describing this on the old forum as I recall but the search function is not being co-operative. As I recall the process is to push out the old glass, possibly gouging out the old o-ring. Note which side is up! Place new glass in place, grease the new o-ring place in groove and start to work around the port pushing in the o-ring till it is seated, using a blunt soft tool. This is what I recall, but do you think I can find the post ?!?! Did you try asking the supplier for an installation guide? -
Flash only going off on 2nd shot
Chris Ross replied to hedonist222's topic in Photography Gear and Technique
it says that you take a test shot and it works it out. so as you say nothing to change. assume you took your test shot? try powering down and doing it again? If that doesn't work, see if other camera flash modes work, powering down between each mode you try. Does the S-Turtle instructions recommend anything in the way of camera settings? -
Flash only going off on 2nd shot
Chris Ross replied to hedonist222's topic in Photography Gear and Technique
This will be because it the strobe thinks the first shot is the pre-flash and it is ignoring that waiting for the real flash to go off. You need to match the camera/trigger combination up to be what the strobe is expecting. The strobe knows nothing about what the camera is set to so you need to change settings so it matches what the camera is putting out. In this case it seems you need the setting on the MF-1 that flashes every time it sees light from the trigger. I'm guessing this as you don't say what you are trying to do - TTL flash or manual flash? Assuming you are trying to shoot manual it seems like it is the flash you need to change settings on. -
The flange distance is different for Canon EF and RF as well as Nikon F and Z mount, the housings are designed so the same lens gear is used for DSLR lenses when mounted on the adapter for mirrorless cameras. The distances will be different depending on what camera manufacturer the housing is for.
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Auto review issue on Sony a7iv
Chris Ross replied to Scubakron's topic in Photography Gear and Technique
Typically what you see on the rear screen is the embedded jpeg and this is influenced by the JPEG settings like brightness/contrast and sharpening. But as far as I am aware the screen and EVF should be displaying the same thing. You could compare the image brightness between the EVF and the rear screen inn controlled (dark) environment to see if there is any difference noted when viewing a previously taken image Some things could be influencing this. First if the brightness settings for EVF and Screen are different. The other thing to consider is that EVF goes quickly from a dull looking natural light image to suddenly displaying a fully illuminated by flash image which is generally more colourful. It may take time for your eyes to adjust when this happens and the auto review time is probably not long enough.- 1 reply
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It should be the same on all housings should it not? This dimension would need to be constant to ensure that the focus and zoom gears will mesh with housing zoom mechanism, though the zoom gear on mine is 4mm thick by a quick measurement so it could be off by +/- 1mm or so and still mesh. If you are trying to get the zoom knobs on adapters to mesh the tolerance I think would be tighter to work well maybe +/- 0.1mm tolerance to ensure the gears fully mesh? Not the easiest distance to measure, on most housings you would need to use a straight edge laid across the port opening and measure from that to the flange.
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You are right, I got lost in all the tests😂. Even so in the tests above it suggests it doesn't do so well even though it focuses close.
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UW Imaging Evolution Thoughts.......
Chris Ross replied to dhaas's topic in Photography Gear and Technique
There seems to be a gravitation towards "good enough", some examples include MP3 music, Phone pics, Go pro videos etc. That's not to say that you can't take rather acceptable photos on your phone etc. it's just that there are so many crappy-average photos and videos getting posted. Granted these tools are constantly improving AI certainly is coming but whether it's a panacea for poor technique remains to be seen. If the tools are built the same way as the large language models by scraping the web for images the risk that it will produce average-mediocre images as that's about the standard on the web by weight of numbers. Even it receives more expert training it seems possible it will produce a certain sameness among images at least initially. It's booming right now but who knows what the future might bring? The boom may continue but there could also be a dot.com equivalent bubble burst when the returns on the investment aren't what was expected. Also whether it takes over or not depends on a lot of things such as some people just want the image, others want to put their own stamp on it and develop the skills needed to get the image they want and enjoy doing the processing. On strobes straight tubes are used most likely as they are cheaper and while sizes are reducing there will be physical limits to hold enough batteries and accommodate the electronics. Size has some advantages - currently bigger bodies and strobes use bigger batteries and can do more shots without needing to be changed. If things get too small they are generally less buoyant so you deal with a heavier rig underwater. The other limitation is button and dial size and placment. The only real complaint about the otherwise nice S-220 strobe if the small controls. Don't want to come across as all negative, certainly some things will get easier as better tools evolve. The limitation for us UW shooters is that the market is relatively tiny and anything on the camera/lens size that benefits us is accidental. Smaller and lighter gear of course is always welcome and everyone will find their won sweet spot of size/weight vs performance. Some of the computational photography tools OM system is coming up with are indeed quite amazing, not all of them are that applicable to UW imaging but its good to see them being developed. -
I don't know enough about optics to give a 100% accurate explanation on the ability of some lenses to work well in small domes. However the basic premise seems quite straight forward which is the ability of the lens to render the curved virtual image and have it all sharp and in focus across a flat sensor plane. We have seen that some close focusing lenses do a particularly good job at this. Certainly a lens being able to focus close it seems helps in this situation, but as I understand things most WA lenses don't have a perfectly flat focal plane and rely somewhat upon depth of field to render images sharp across the sensor plane. I notice that the newer Sony lenses are particularly good in smaller domes, while it seems the RF 15-35 isn't as good even though it focuses close. The amount of curvature of the focal plane may interact with the curved virtual images in ways that are more or less beneficial. A lens may have a flat field at infinity and develop field curvature as it focuses closer and the direction of curvature can reverse as well. The shape of the focal surface can be found on Photons to Photos optical bench. For zooms it is only available at infinity, some primes allow you to adjust focus and observe how it impacts the shape of the focal plane. If you look at optical diagrams for the lens elements you can see that the zooms within a given manufacturer have similar layouts. If you compare the Sony 16-35 f2.8 GMII to the Canon equivalent the lens element layout if quite different and seems to be different to earlier Sony 16-35 zooms. On the issue of microcontrast, you could of course test that by taking shots with the 140mm dome a little closer. Not sure why it would be less in the 140mm dome.
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Fuji camera + tokina 10-17?
Chris Ross replied to boduoguo's topic in Photography Gear and Technique
It depends - is the 55mm adapter one that was sold as allowing use of adapted Canon EF lenses with Fuji? If I recall correctly the last line of the port chart used to include an adapter designed for this purpose and the Nauticam gear would mate up to the Zoom knob on the adapter. If not you would need to work out the correct extension to use. -
Fuji camera + tokina 10-17?
Chris Ross replied to boduoguo's topic in Photography Gear and Technique
In theory it should work just as well as the Tokina 10-17 on any other APS-C body, so same zoom range and image quality. The only variable that is unique to the Fuji- Tokina 10-17 combination is how well the adapter plays with with the Fuji cameras. You could search around to see how the AF works with various adapters on land based applications. Metabones publishes known limitations for their adapters. https://www.metabones.com/products/details/MB_EF-X-BT1 -
RETRA Lithium-Ion Battery Pack
Chris Ross replied to Jay-11's topic in Lights, Strobes, and Lighting Technique
The specs say it's 7.2V so it must be either 2 or 4 cells. -
Nikon 5T Diopter vs wet lens diopters
Chris Ross replied to shokwaav's topic in Photography Gear and Technique
The magnification obtained with the 5T is not as high as typical wet diopters like the Nauticam SMC-1 which achieve something around 2x magnification. It will get you something like 1.3x on a 105mm macro lens. Also it means you can't shoot larger things that you find as the lens no longer focuses to infinity, being able to take the diopter off UW is the bige benefit of thaw wet lenses. -
Can't help with the extension required. However I suspect the screws are really not needed when you have a vacuum. If you have the reported 200 mBar vacuum on the housing the the closing force is around 22kg. The extension ring if push and turn and it's not going to come apart with that type of closing force. I see the Type II ring is now offered, it's still push and turn but has an internal lock.