Chris Ross

It seems the issue is the difference between AF-C and AF-C plus tracking. I just played with my OM-1 and it was quite capable of using a very small AF point in AF-C, however for AF-C + tracking it draws a box around what it thinks you want it to track and this is where algorithms for choosing a subject come into play. It will lock onto what the system thinks you want and generally it will be the body part or object with the best contrast, but it depends on how it is programmed and it seems it chooses to use a bigger box when tracking is used. Subject recognition is the same deal it depends on how well it recognizes your subject. Another aspect of this is how well the Image stabilisation works- it can be particularly helpful in keeping the AF point stable on the subject if you sway a bit. If you move in and out in super macro you will be adding in the the AF speed and whether it can keep up as well. I find I'm not so stable as when I was younger and the IS on the OM-1 is a godsend. It really helps keep you subject framed properly - the smaller sensor is easier and quicker to accelerate and seems it quite stable enough to do hand held focus stacks. It seems to me that how well you like a particular AF system is a little personal and depends how well it can compensate for your instability. Water should slow things down a bit (unless you are dealing with surge or current) and again I think trying out some systems on land would be a good starting point.

Seems like the best thing you could do if it is available is to go to a physical camera store and try a few candidates out, Bring along a small model of some type which would allow you to test for precise AF placement. I know my OM-1 has a very small AF point available, the limiting factor is probably if the subject has enough contrast and beyond that holding the camera sable enough at high magnification. The stabilisation is a big help here. The OM-1 seems to be a favourite among macro bug photographers.

Welcome Lidas, good to have you join us.

welcome aboard Rob, good to have you here. As Davide said, doesn't seem possible to do anything at Wetpixel. It's basically a ghost ship, you can still post and reply there and search old content, but that's about it. Apparently it has been set to a mode where only logged in members can see posts there and there's very little activity these days. But having a profile means you can lookup old content there as long as it stays up.

Hi Tom, sorry to labour the point, I wasn't 100% sure I was interpreting it properly myself so I went ahead and did a test myself. I set up the camera in a housing and dipped the flat port in a tub of water and took a photo of a ruler with the lens set at 1:1. This is with an Olympus 60mm macro which has a switch to move it to 1:1. I lowered the housing on a slider into the water till the ruler came into focus and locked it in place. Here's the setup: And here's the result: You can see that the sensor records a field 17mm wide which matches the reported width of the m43 sensor of 17.3mm . I measured the working room from the port and set it at that position but found I needed to back off to achieve focus, which means this effect gives you more working room at maximum magnification. I cross checked by lowering the port a little and it would no longer reach focus proving I was at minimum focus distance and achieving 1:1 magnification. I think you might be right about having more airspace inside the port it would allow you to focus closer to the port and record a larger virtual image - but it would be best to test that. It seems counter intuitive but the link I provided above on flat ports explains. the critical points are: A flat port magnifies because you are looking at a virtual image which appears to be closer so appears larger. to record the virtual image you need to be able to focus on it and are limited by the virtual image distance. If you get steadily closer to the subject the virtual image gets closer until the lens can no longer focus on it. this occurs when the subject is a distance where 1/1.33 = 0.75x magnification in air would occur. The virtual image at this point is 0.75 x 1.33 = 1.0 magnification. This means when the lens is focused at 1:1 the subject is at the same distance it would be if it was at 0.75x magnification in air. You can't magnify more because the lens won't focus any closer. If you scroll down to the paragraph first the flat port it will explain. 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...

Marelux have a +5 they have just released recently haven't used it of course but could be decent quality. You could ask Phil Rudin if he has tried it?

I've no doubt it works well for a lot of people. I'm happy with what I'm doing and I think it suits some people better than others - no judgement just do what you find works! I believe Capture One can do something similar but I haven't dug and explored how to do it as yet.

The Nauticam port charts at one time included some references to using SMC and CMC diopters on the same lens and the CMC-1 lens was slightly more powerful than SMC-1. The CMC was designed around compacts which tend to have shorter focal lengths so need more power to achieve similar magnifications. I expect this is why Nauticam recommends the CMC-1 with the 28-60. I'm sure the SMC-1 would work, just giving slightly less magnification than the CMC-1. The port chart shows that you get 0.9x magnification but the working distance is between 55-80mm. This means it won't focus except in that very narrow band. I expect it could be a little frustrating to use compared to a proper macro lens. If you are talking about a s35 sensor, assume you are shooting video - I imagine it could be tough to position the rig particularly if you are using a tripod for macro video. You would actually get 1:1 with the 90mm so would be filling the frame with a subject about 25mm across - so I would be asking the question if you need that sort of magnification before deciding what you want to do, which of course depends on what subjects you have in mind. That's more magnification than you would get with the 28-60/CMC combo. The 90mm on an s35 is equivalent to a 135mm lens so you may be needing to back off to far with larger subjects.

You can also do this in your file manager if you name your processed images with species or area or whatever fits best and you can utilise the directory structure to keep it in some sort of order. Searching that is also quite fast, though for Windows users the MS file explorer can be present problems (like the green ribbon of death) so I use Directory opus a third party file management software. I can search from the every top of directory tree to find the file I want. If an image is properly named I can find it no time at all. Going back to the Raw file takes a little longer - I store these by date and area and using the EXIF data I can get back to the Raw images pretty quickly as well. The advantage of this system is it is transparent - not all tied up in a proprietary format. I store all my processed files as a full size layered tiff so it's easy to go back and tweak the editing.

Hi Tom, this is not what I am saying, of course you can get greater than 1:1 through a flat port if the native lens magnification is greater than 1:1 . I'm saying that the 1.3x magnification seen through a flat port is due to the lens focusing on a virtual image which is closer than the actual object. It can only focus on that virtual image up until it reaches its minimum focus distance. To magnify greater than 1:1 it needs to focus closer than its minimum focus distance. It's easy enough to test - set you lens to minimum focus distance behind a flat port.\ and photograph a ruler with port immersed in water. You can calculate the magnification if you know the sensor dimensions.

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.