Ps., almost forgot. Just got the MFO (mighty fine optic) a few days ago as it was back-ordered (from Backscatter). In the bag ready to take it out but waiting for the rain to stop (predicted for later today)

I just shot the MFO against some ISO targets. As far as I can tell for micro 4/3 (30 macro Oly, 30 macro Pany, 45 macro, 60 macro and 90 macro, there is no obvious increase in edge quality. Perhaps it has great use only in FF cameras.

I talked to the Backscatter guys at the Long Beach scuba show and they said of course it is only for FF. I wish they told me that BEFORE I paid them for it.

Bill

6 hours ago, bvanant said:

I talked to the Backscatter guys at the Long Beach scuba show and they said of course it is only for FF. I

Bill

The MFO-1 is listed in the N85 datasheet from Nauticam so meant for micro4/3 as well.

Well I tried it with every macro lens that I know about and it works in the sense that you get some more magnification but as for edge aberration improvement, it is not obvious to me.

BVA

It's been a dry spring for me but I hope to try an A/B test later this month. I was impressed with the MFO sharpness but it was also a new lens (Canon 100mm RF) and port. So next time I'll shoot some without, for science. 🔬

Not dry here at all. It took a week but the sun did break out for a short while (remained mostly cloudy) yesterday so was able to give the MFO a tryout - the rain commenced just after getting home! Raining hard with wind now.

I also tried out my new float rig (note all the float arms). The UW shots shown here were taken at f/8 with auto-ISO. Note that I did a vertical crop of the two-fish shot. Just the stickleback is in focus.

This is in a protected spot as the wind was blowing enough to cause white caps and small breakers on the shore of the main lake body. I stood (with waders on) where the camera is in the setup shot and pole-cammed the results using the camera's intervalometer. Note the brown bottom. Water is stained so that a very heavy hand was used for post-processing.

For this shoot I was in the two to seven inch working distance range so right in the range for which the MFO was designed. The bare lens is about a foot minimum distance (Nikon 105VR-AFS F mount on Nikon D4S).

Edited Saturday at 09:19 PM1 day by Tom Kline

PS, It just occurred to me that with the MFO the max magnification is reduced compared to using just a flat port so looked up the Nauticam port sheet. Nauticam states it is 1.1x for the 105 Nikkor AFS-VR with the MFO. But max with a flat port is 1.33x thanks to the refractive effect of water.

Is this what Alex reported? I thought he was saying he asked Nauticam for magnification just less than the SMC. Confused I am.

Bill

1 hour ago, bvanant said:

Is this what Alex reported? I thought he was saying he asked Nauticam for magnification just less than the SMC. Confused I am.

Bill

Consistent but do not forget the SMC mag is quite a bit higher than what the lens does alone. The real goal IMHO is the large gap in minimal working distance. For example I would not normally use the 105 without a wet lens or internal diopter at this location due to very low viz. At 1:1 there is too much distance, can only work very close.

BTW because the MFO is so light and compact it is easy to bring along with an EMWL. I actually had the 130 EMWL with me along with other options I did not use (remote control cable and 45° finder).

2 hours ago, Tom Kline said:

PS, It just occurred to me that with the MFO the max magnification is reduced compared to using just a flat port so looked up the Nauticam port sheet. Nauticam states it is 1.1x for the 105 Nikkor AFS-VR with the MFO. But max with a flat port is 1.33x thanks to the refractive effect of water.

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.

2 hours ago, Chris Ross said:

It's already been shown (Has it?) 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. (Why would Nauticam not post the magnification of the complete optical system?) In addition with the MFO it will focus a little closer. Focusing closer is how the magnification is achieved.

My comments in bold.

15 minutes ago, Tom Kline said:

My comments in bold.

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 Theory

One 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...

I believe you are incorrect. One can certainly focus UW > 1:1. Folks have been doing that for years, e.g., using 1.4 teleconverters or internal (on the lens inside the port) diopters. With domes one is focusing on a close virtual image - this is the distance the camera lens focus is set at and can be read off the focusing scale (with a transparent housing!!!). Many lenses do not focus close enough to allow them to work behind a dome such as 50mm f/1.4 lenses with a typical min. focus distance of 0.45m. This is a big problem as well with medium format cameras. I know this because I have the Hasselblad EL housing that uses 8" plastic domes. The 50 and 60mm wide angle lenses that work with the housing focus to just 0.5m so special Zeiss made diopters were sold. As it took me years to find them I used standard off the shelf diopters that also worked.

With a flat port one can typically use the entire focusing range of the lens. For example with the camera lens at infinity (virtual image distance) the lens is focused close up with the amount dependent on diopter strength so further rather than closer.

Edited yesterday at 06:24 PM1 day by Tom Kline

Look at what Alex is testing!!!!!

7 minutes ago, Tom Kline said:

Look at what Alex is testing!!!!!

Doomsday Device!

@Alex_Mustard What is it?

21 minutes ago, Davide DB said:

Doomsday Device!

@Alex_Mustard What is it?

ROTFL!!!

My first guess was supermacro, maybe much longer working distance than any of the SMCs. Another guess is that instead of an add-on lens it is a complete port, sort of a macro analog of the WACPs. 105 or 60mm goes inside??? Kind of late for a 60 but might work with the Z50 macro.

6 hours ago, Tom Kline said:

I believe you are incorrect. One can certainly focus UW > 1:1. Folks have been doing that for years, e.g., using 1.4 teleconverters or internal (on the lens inside the port) diopters. With domes one is focusing on a close virtual image - this is the distance the camera lens focus is set at and can be read off the focusing scale (with a transparent housing!!!). Many lenses do not focus close enough to allow them to work behind a dome such as 50mm f/1.4 lenses with a typical min. focus distance of 0.45m. This is a big problem as well with medium format cameras. I know this because I have the Hasselblad EL housing that uses 8" plastic domes. The 50 and 60mm wide angle lenses that work with the housing focus to just 0.5m so special Zeiss made diopters were sold. As it took me years to find them I used standard off the shelf diopters that also worked.

With a flat port one can typically use the entire focusing range of the lens. For example with the camera lens at infinity (virtual image distance) the lens is focused close up with the amount dependent on diopter strength so further rather than closer.

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.

You are still getting a 1.33x mag if that is the goal. Distance depends on focal length, i.e. greater with 105 compared to 60.

I have rather limited facilities to do testing here - see above. Working distance can vary depending on ones port setup. One trick is to have a bigger air space (longer port) to reduce water path. Cannot use that trick if configured to use the EMWL as one needs a small air space inside the port.

9 hours ago, Tom Kline said:

Look at what Alex is testing!!!!!

Don't want to derail discussion. Once I've tried it, I'll share more details. It is designed to do a different job from MFO-1. Despite looking production ready with the finish, it's early stages.

Alex

Hi Alex

What will be the job of the MFO-2 ?

Hugues

2 hours ago, Tom Kline said:

You are still getting a 1.33x mag if that is the goal. Distance depends on focal length, i.e. greater with 105 compared to 60.

I have rather limited facilities to do testing here - see above. Working distance can vary depending on ones port setup. One trick is to have a bigger air space (longer port) to reduce water path. Cannot use that trick if configured to use the EMWL as one needs a small air space inside the port.

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 Theory

One 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...

1 hour ago, CaolIla said:

What will be the job of the MFO-2 ?

Very different to MFO-1. So not relevant to the discussion here (I didn't bring it up!).

Since many still struggle with the job of the MFO-1 - it is to give you a bit more magnification than the lens does on its own (while improving IQ and AF a bit).

2 hours ago, Chris Ross said:

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 headed "First the Flat Port" it will explain.

Understanding Flat Port and Dome...

Understanding Flat Port and Dome Port Theory

One 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...

Loud and clear!

Interesting result! I have not done anything like that although your shoot reminds me of shooting developing salmon eggs in situ. For that I tried various combos mostly with internal diopters as well as the Nikon Micro-Nikkor zoom lens with NO focusing (AF off and no focusing gear) - port length was fixed at maximum length (the lens extends) - zooming used to control image size. Main issue was very shallow depth like your setup.