Chris Ross

People have posted images further up the thread showing the change in image scale with the MFO. I also seem to recall reading something about the flat port magnification - stating that flat ports also produce a virtual image and that the virtual image is closer to the sensor than the subject. So the1.33x magnification is produced by focusing on the closer and larger virtual image. But when you are operating at 1:1 the lens can't focus any closer and can't actually image the 1.33x virtual image and it stops at 1:1. This is my interpretation and I know enough about optics to be dangerous! 😅 This seem to say to me that you can actually only reach 1:1 with a lens behind a flat port. this link explains the virtual image but doesn't seem to take the logical leap that you can't get beyond 1:1 with a 1:1 lens in a flat port. Happy for others to dispute this conclusion with their reasoning. Also I don't see how a dipoter could produce less magnification while also focusing closer than the bare lens. They operate by allowing the lens to focus closer and restrict the range that is in focus just like the MFO does. If my reasoning is correct it explains the magnifications that Nauticam posts. Understanding Flat Port and Dome...Understanding Flat Port and Dome Port TheoryOne of the key features of underwater photography is the dome port. Despite it's ubiquity, it's effects are largely misunderstood or at the very least, poorly explained. In this post I'm going to...

That is a huge increase. My Raw files are 17 MB and the processed tif (with layers) is about 100 MB when stored as an 8 bit file with LZW compression. so a 6 x increase. doing similar with an 80MB file should make a 470 MB file. Is the file 8 bit or 16 bit? does it have layers? Also note that apparently the compression algorithms don't make 16 bit files smaller for seem reason and can even make it larger. This is what I don't like about Lightroom - all of this storage stuff is opaque, it's not immediately obvious how it is taking up so much space. Adobe is not really interested in solving storage problems - their answer is "storage is cheap". On the topic of disk space, I assume you empty the trash regularly. I try to go through my images when I upload them and throw out the unusable and also duplicates etc. Doing this in capture one they end up in the session trash and the raws don't get deleted but get put in the trash. I believe Lightroom does something similar. I just hit throw out trash on my setup and the main drive folder reduced in size 2.38 to 2.18 TB deleting 61,000 files. I know it's been a while but I certainly didn't delete anywhere that amount of image files - it's all the add-on files the system produces. The 0.2 TB would represent about 11,000 Raw images for me. I looked at my main image folder - it has 19,000 files, 10,000 of them are in the Capture One folder. It's worth doing a bit of digging to see where all of this is hiding.

It's already been shown that the MFO gives slightly more magnification than a bare lens in some UW shots posted above. So this means that the 1.33x from the flat port is a given and the magnification is with respect to that you get with a bare lens. so for the Nikkor the actual magnification is 1.33 x 1.1 = 1.46x. In addition with the MFO it will focus a little closer. Focusing closer is how the magnification is achieved.

The wide dynamic range will rarely come into play in macro shooting with artificial light. UW contrast tends to be quite low much of the time, one exception being sunballs. MP is a similar story, mainly come into play when printing Large, natively a 20MP m43 sensor will give you 43 x 33 cm natively at 300 dpi which is close to A3 size. A well exposed image can be re-sampled to around double that resolution for printing with good results. The main benefit of big dynamic range is preventing posterisation in gradients like a slow gradient of surface water, you need to process in 16 bit to get this benefit. I think 12 bit vs 14 bit is likely little difference for this purpose. I think for most people the benefits are small to not there for 99% of their images. It's more case of if you can afford and want to and are prepared for the limitations sure go for full frame. If you are making your living from it - I expect there are benefits for those cases where the extra quality is required. But there's plenty of people taking great shots with m43 professionally as well. This guy takes some amazing shots with an OM-1: https://500px.com/p/sulasulacom?view=photos - no UW stuff but some of the high ISO bird images are quite amazing!

This is true, though you can certainly have some very light WA setups in m43 like a 4" zen dome with 8mm fisheye and a 230mm dome never enters imto consideration.

I don't use lightroom, however I expect the problem is that Lightroom catalog keeps records of everything and probably is not efficient at cleaning up the trash. I have heard other say they make new catalogues and export everything to their main computer (with way more storage) and wipe the laptop clean. I think you are saying you only have one computer though - is this the case? My workflow is somewhat different - I have a laptop for travel and a desktop at home. On the desktop I have Capture One plus PS. I do preliminary processing on Capture One and select images to fully process and save that on the main computer as a tif file. I also produce a a 1200 pixel long side jpeg which will be around 250 kB which is also stored on main computer. I could keep the JPEGs on my laptop as well but don't. I have a folder with 13,000 files (mostly jpeg) which takes up about 4GB. I think this demonstrates that Lightroom has a lot of overheads to maintain your smart previews, compared to storing a small web-size jpeg. This may be a solution that saves some size for you - I find I can find any file I want using file manager search functions as every file is named by subject. I think keeping a master catalogues of everything on an external hard drive which is updated from a trip catalogue which can be wiped after updating the master would be what you need to do. Others could fill you in on the details of how to do this.

The key word is necessary. The meaning of this will vary among people depending on a lot of factors. For example if you only post your photos on Instagram then you would be hard pressed to tell the difference between a well taken shot with a TG-7 and the best full frame setup. If you don't sell your photos you only have to please yourself. If you enter competitions the judges don't know which camera you used. Unless you are talking A2 size and larger m43 will do a perfectly good job of printing for you. the second consideration is the OP question, which would you buy- everyone is jumping to best image quality, but there are other considerations which people might consider including: $$$ - full frame setup is always more, camera, housing, lenses ports are all more expensive size and weight, the lenses for m43 are way smaller for starters. size and weight impacts travelling and also pushing the rig through the water and getting into tight spaces Crop factor - the Olympus 60mm macro will get you the same framing as FF 100mm macro at 2x without mucking around with closeup diopters and apparently you don't need to shell out for the MFO. You can get the equivalent framing to a 100mm macro at 4x with the 90mm macro - no diopter and more working distance. Plus at given framing you get more depth of field, generally a plus for macro. wide choice of macro lenses - for m43 you have 90mm, 60mm, 45mm and two 30mm options You can add wide angle capability with minimum extra space taken up in your bag - a 4" Zen dome and and an 8mm fisheye take up next to no space. The size and weight penalty for macro is certainly less than it is for wide angle, but you might stretch the definition to include WA macro which can be done with m43 with a lot smaller gear. I certainly find framing up easier with a macro lens without diopter you can find the subject from a distance and slowly move in closer and re-focus as you go. So for me I don't think I'd change from what I have now. An OM-1 with 60mm macro, though I might consider adding the 90mm macro at some point. It's not a video machine but it will shoot no frills video. The choice may change depending on how much interest there is for video and what you want to do with it.

I agree with all of this, you can get macro range from compacts with a diopter, but it locks you into a narrow shooting range and makes life difficult in that you have to get into the right focus range to even see anything to aim the camera. A regular macro lens allows you to stand back frame and refocus as you move closer . It does depend on how small you want to shoot things as well, the little compacts only focus close at the wide end. If it's shooting things that are around 50mm long you might be able to do something without a diopter, particularly if you went with a G5XII which focuses a lot closer than the G7XIII, but has more limited housing options.

So Phil, I had a look at the Marelux wet lenses just now, is there some sort of port chart to work out which lenses they will work with? At the moment there is just the lens posted with no additional information I could find.

Best course of action - suck it and see. Everyone's standards are different and it would help you a lot I think to take 5 minutes of the dive to shoot a subject - even the sandy bottom at f5.6 through to 13 to give you an idea of what's possible. A flat surface is good as you're not wondering if the corner blur is due to aperture shot or if it's significantly closer to the camera.

I think you need to consider that the WWL/WACP options are not really interchangable the wider angle of the fisheye makes every thing much smaller in the frame, though your subject may not shrink much due to the barrel distortion. Also you need to watch corners much more closely for stray freedivers, fins etc. Your experience will help with deciding if this is going to be an issue for you. So the questions to ask is how often you zoom in from maximum view with WWL? This post compares the field of view of a 14mm rectilinear lens which is close to what you get with a WWL with a fisheye and shows the impact of zooming into a 28mm equivalent lens and a 15mm fisheye with a 2x. I can see some options. get a 140mm dome and use with a fisheye or you could consider the Laowa 10mm A WACP which would use your existing lens an adapted 8-15 fisheye with a SONY 2x which would completely replace what you have now - one system for Baja freediving and the same system on reefs, but having the advantage of full fisheye on the reefs. The last option will give a full fisheye for reefs with zoom capability for CFWA. It will be quite heavy UW which may be an issue. There's lots of posts on how this is done on this site and it gives a very flexible setup.

You could ask google there's lots of marine grade adhesives around, anything used on a boat would probably work, choice may be dictated by container size, you probably don't want to buy a full cartridge just to glue a single pad. This page reviews a number of marine adhesives: https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.practical-sailor.com/boat-maintenance/marine-sealant-adhesion-tests&ved=2ahUKEwi2ppjeucqNAxXThq8BHXyaHnEQFnoECDkQAQ&usg=AOvVaw2wZJMvDyWlyNygjUjf4VwB You might go to Ship's chandler to see what they have to offer.

The clear recommendation is to have the focus limiter set to the full range. Nauticam and Alex have both mentioned this in other posts and here. This makes sense because using the RF100 as an example infinity focus is at about 1m working distance with MFO fitted. If you turn on the focus limiter it limits the lens to the 260-500mm range. WIth the MFO full range gives 56mm to 1072mm from the port chart so limiter would restrict you to something like 56 to 200mm at a guess, possibly less range.

Thanks for weighing in Alex, the AF behavior described certainly sounds like a camera/lens with some sort of problem or settings issue to me. The OP mentions a fish near in focus doesn't snap to focus but instead starts hunting. I'm thinking the MFO probably shouldn't be expected to help with an issue like this.

Don't really agree with the TC comment, it is proposed to put a 1.4x on a 50mm lens to get a 70mm lens , yes there's more water compared to the bare 50mm but it's less water than framing the same way with a 100mm macro and lots of people use them. With crop factor that's like a 112 mm lens on a full frame camera.

The MFO is designed to counteract the abberations caused by refraction of light through the flat port glass. These aberrations get progressively stronger as you go from centre of field to the corners. The camera in question here, the R7 is APS-C so much of the corners are cropped out of the frame compared to a full frame sensor camera. This means the sharpness benefits will be a little less. The aberration are worse with shorter focal length lenses like a 50-60mm lens on full frame and this is where the biggest benefits would be expected. In the past the aberrations with a 100mm range macro lens were accepted as there wasn't really an alternative and they were relatively small. I agree a 100% corner crop pasted side by side with and without the MFO would be of interest. I think it is worth checking if the camera/lens combination also hunts on land , try shooting something in similar light levels, you could check the ambient exposure on your next dive to know the sort of light level you might need. It would also be worth asking if others have experienced hunting as bad as you describe with the RF 100mm. Also check what AF points others use, do use a single centre point or an array of some type. I would also suggest trying to find someone else with an RF100 you could try and/or an R7 body to compare how they perform compared to your gear. Also confirm you have the limit switch set for the full range. of focus.

Don't believe it is , a lot of compacts used to have accessory converters to increase the focal length that went on front - the only option as the lens was not detachable. Interchangeable lens cameras generally use a tele-converter between lens and body, probably because it a cheaper solution with smaller optics compared to a full diameter optic attached to the front of the lens. So one could probably be designed, but the market would be quite small I expect, mainly barbecue conventional 1.4x and 2x converters do such a good job at a reasonable price point.

That's exactly why you have the variation - buoyancy is equal the the weight of the water displaced by the monitor, the bigger it is physically the more buoyant, if you have more air space inside it is more buoyant.

Wet lenses generally allow you to focus closer not to increase the focal length. I think this has been asked before and the only option was a Canon 50mm f1.8 prime lens as far as what would fit in the housing goes. You might be able to add a Kenko 1.4x to the 50mm f1.8. I found a review of the 18-45 that said it was 77mm long at max extension The 50mm f1.8 is 46mm long and extends to 60mm long and the Kenko is about 20mm thick so it might just fit and the lens would just hit the port glass at minimum focus. Min focus would be about 200mm from port. You would be stuck at this focal length and just be shooting fish portraits the whole dive. Any wet diopter works by allowing the lens to focus closer, it doesn't give more reach, the KRL-05S is no different to any other diopter.

If that is the extent of the length change of the lens, behind any sort of dome I can't see that being a big issue, The sharpness might deteriorate a small amount, but there's no shortage of lens that zoom like this. In any case the usual situation as I understand it is that the manufacturer will test the lens at its widest which is where positioning is most important. Even internal zoom lens may move the entrance pupil around a bit.

Something like this should work: https://www.jaycar.com.au/m3-x-6-3mm-tapped-nylon-spacers-pack-of-25/p/HP0920 If the screws are M3 x 10 the spacers would be at most 7 or 8mm long to have enough thread showing through to screw into the housing. If the spacer is threaded it would make it captive to the board, possibly making installation easier.

Agree that there is no harm trying out existing domes you may have, however it also places the lens further from your subject, reducing available working distance and magnification, which is why I think the 4" macro port is favoured. It depends on what your targets are if this will present a problem or not.

I would suggest matching your UW lenses to what you might want to shoot UW. UW shooting is different in that the goal is to get close to minimize the amount of water between you and your subject. Not all good lenses translate well into UW shooting - the main requirement is close focusing and even then it pays to choose lenses that are proven UW performers. A lot depends on what you shoot and in in what conditions. Clean tropical waters are somewhat different to shooting in temperate waters where there may be lower visibility and more particulate matter to deal with. In the tropics for WA I like my adapted Canon 8-15 for wide angle work and it works nicely for CFWA as well. In temperate waters the narrower fields of something like a 20-24 lens are a little easier to deal with and you can swap between things like fish schools and larger single fish, big nudis and other critters which are physically large enough to shoot with a mid range zoom. The Tamron 17-50 I don't know I've heard of anyone using UW, the min focus at the long end seems a bit too long to work well UW. The 20-70 on the other hand has been used by a few people on the forum and is reported to work well. The 6 and 8" seafrogs domes might be a little small and not have ideal extensions to work with lenses in the 16-17mm range and corner performance may suffer. This becomes less critical at narrower angles of view and 20-24 lenses will not have the same penalty. Fisheye lenses are different and work quite well in smaller dome sizes. Personally I would try using what you have now for a while and see what you find you are missing out on in experience. Again though this might vary depending on where you are diving and the subjects you find you like.

This is the standard way items shipped from overseas are handled. Any business can only collect tax on items sold in country or in this case the EU, they collect this and pay to the government. They can't collect any tax or import duties charged when the item is imported into another country as they are not setup to do this and many jurisdictions will only allow collection at import. That is charged prior to the item being imported being released. If you click on the ? next to Shipping, this pops up. There is also a footnote next to the price which refers to a similar note on that page: If I was to buy one and import into Australia, the importer would collect 10% GST on the items value including shipping costs. Depending on the item they could also collect customs duties and also their handling fee. You would need to inquire with the importer about how much they would charge.

That 8-15 gear is for Sony either alone or with a 1.4x, it's reversible to do both services. Probably need to make it longer to use with a 2x.