RX100 M2 versus RX100 M3 Lens Differences

[DelrayDM]

I have not noticed any difference in the lens between the RX100 and RX100 M2. So in this article, whenever I refer to the M2, I am also referring to the original RX100.

There is a difference in the maximum focal length of the lenses in these cameras, but that will not be the subject of this article. This article will discuss the differences in these lenses for wide angle underwater use.

The RX100 M2 lenses at fully wide are 28mm equivalent focal length.
The RX100 M3 lens at full wide is a 24mm equivalent. This means that the RX100M3 field of view at full wide is a little bit wider than the RX100 and RX100M2 at fully wide.

While this may not make much difference to topside shooters, there is a very significant difference in these lenses for underwater photographers.

That difference is that the M2 when at fully wide, the lens is shorter than at full telephoto. So when a housing manufacturer designs the port for the M2 , it is designed just long enough to fit the camera with the lens at its longest; in this case, when it is zoomed fully telephoto.

The M3 when fully wide, the lens is at its longest. Therefore, when a housing manufacturer designs the port, it will be designed just long enough for the M3 to be zoomed fully wide.

Why this is good news to underwater photographers takes a little explaining.

To use a wet-mate wide angle conversion lens it is mounted on the port, and a very important factor in the resulting performance is the distance between the camera lens and the back lens of the wet-mate wide angle conversion lens.

If the camera lens is quite a distance away from the wet-mate wide angle conversion lens, one of the undersired results is that the camera lens will 'see' the back of the wet-mate wide angle lens. Other important factor is the the front of the camera lens does not optically line up with the back lens of the wet-mate wide angle conversion lens. For convenience we call the total results of this problem "vignetting."

If the distance between the camera lens and the wet-mate wide angle lens is very short, the camera lens will only see the lens part of the back lens of the wet-mate wide angle lens, and it will be better optically aligned with the wet-mate wide angle conversion lens which is exactly what is desired.


On the left an RX100 M2 at full wide. On the right, an RX100 M3 at full wide.


On the left an RX100 M2 zoomed to full telephoto. On the right, an RX100 M3 zoomed to full telephoto.


RX100 M2 fully wide. Please ignore the tenths of millimeters in these photos; I have never been trained as a machinist.


RX100 M2 fully zoomed



RX100M3 fully wide



RX100 M3 fully zoomed




The distance between the front of the camera lens and the back of a close-up lens is not as important as the distance for wide angle lenses.

 

[Interceptor121]

Rx100 m2 fully wide length 73.88 length at full zoom 73.43 as the mark I and III the lens is longer at the wide end so this measuring proves nothing???

---------- Post added July 11th, 2014 at 06:59 PM ----------

You also have not considered that vignetting is not just seeing the back of the lens but also the front ring or the hood.
For example when you use the Inon as flat lens the camera does not see the back of the lens but the front you put the housing in water and the vignette stops however once you put a dome on this cancels the effect of the water and you need to zoom in.
So if you need to step zoom to 28mm on the mark III the lens will go back further away from the port, this will in turn affect the demagnification of the wet lens which means a reduction of field of view compared to the mark I and II you then need to evaluate how much are you loosing to see what you get.
At telephoto end the Mark III port will be further away from the close up lens that you mount on the port which means it will perform even worse as the lens as a magnifying glass and the power reduces with your increasing distance from the close up lens though this won.t be massive as the 70mm zoom is already poor this will definitely not be good.
Let alone the fact that increased distance between the lens and the port generates chromatic aberrations known as fringing so not only vignetting but also optical quality suffers.
The lens design for the Mark I and II with the lens nearly same lenght at wide and full zoom guaranteed the widest field of view with fisheye lenses and the maximum magnification with diopters, with the new lens the only scenario that will be better will be the use of flat lens at 24mm that will maybe give you 110 degrees versus the 104 you were getting before however with a dome instead of getting the nearly 158 you were getting before you may be looking at much less now depending how far back the lens goes when you are at 28mm probably around or less the nominal value of 144.5 but this needs proof.
In short wet lens performance of the Mark III is worse than the previous releases and the range of field of view or magnification you can achieve narrower pretty much the same situation that occurred to Canon S series when the S100 was introduced or with Panasonic when the LX5 came in

 

[DelrayDM]

The Inon UWL H100 works with the RX100M3.

With the Inon Dome Unit II on the UWL H100, it will vignette at full wide (24mm equiv), but a tap on the zoom lever to 28mm equiv eliminates that. I'll try to get pictures Monday.

No vignette with Ikelite W-30. This shot is at f/4. I did not have room in the sink for strobes, and since this was only a vignette test, I used a couple of Sola lights.

,

 

[Interceptor121]

I guess it depends what 'it works' mean. I don't think measuring the mark I and II camera proves anything to this cause the lens is perfect on those two versions. However the fact you have to zoom to make it work on the new one means lens further away from the port that in turns means narrower field of view compared to the mark I or II cameras where at 28mm the lens is fully extended. Certainly with the flat lens at 24mm if there is no vignette for the same reason you get a wider field of view but that if rather have 104 degrees and 152 instead of 110 and 145. For video the mark III may be a fine camera as active steadyshot crops at 28mm all the blur in he corners but I don't see any benefits for photographer coming from the new release

 

[DelrayDM]

Macro with RX100 M3

First lets mention that the RX100 M3 has a "24 to 70mm lens" (equivalent to a full frame system).

The RX100 M2 has a "28 - 100mm lens" (equivalent to a full frame system).

At first glance, we might think that the M3 is not as good for "macro" as the M2 because the lens has a shorter maximum focal length.

At full zoom, the M2, would not focus any closer than 64 cm for me underwater. The M3 would focus for me as close as 30cm. (Remember I am doing this in the kitchen sink looking at a grid, not a swimming fish.)

What does this mean in image size?

With the M2 at full zoom (full telephoto) an object 22 cm wide (about 9 inch) will fill the image horizontally.

With the M3 at full-zoom (full telephoto) an object 16cm wide (about 6+1/2 inch) will fill the image horizontally.

So should we say that 'out of the box' that the M3 is better than the M2 for photographing small creatures underwater?

I don't think there is a simple answer to that at this time.

First, let me remind readers that when zoomed wide, both of these cameras focus very close to the port. So close, that your problem would be lighting the subject. Like you do not have room for two fingers between the port and the subject But when you zoom wide and have the lens almost touching the subject, very small subjects will fill the image.

So you can photograph very small things when these cameras are zoomed full wide, but underwater, will the creature let you get that close? This is why I pretty much only consider using these cameras zoomed in most of, if not all of, the way to telephoto. Maybe it depends where in the world you are diving.

Results with Subsee +10 or Saga +10 wet-mate close-up lens (camera zoomed fully to longest focal length):
M2 - an object 3.6 cm wide will fill the image horizontally.
M3 - an object 6.5 cm wide will fill the image horizontally.

So did I say that the M3 is 'better' than the M2? With no wet-mate close up lens, maybe, but with a +10, the M2 is 'better'.

This might seem wrong or weird, but this is because the 'worse' the minimum focus distance, the "better" the close-up lens works. There is an easy-to-use calculator on the Reefnet site here.

With the Nauticam Super Macro Converter on the RX100 M3, zoomed fully, an object 3.8 cm wide (1+1/2 inch) will fully fill the image horizontally.

The RX100 M2 with a Reefnet Subsee +10, or a Saga +10 and the M3 zoomed fully, an object the same size will fill the image horizontally.

As intercepter121 has brought up, the distance from the front element of the camera lens to the wet-mate close-up lens will affect performance.

Hopefully next week I will be able to post some comparitive shots with various close-up lenses at various aperture settings so we can see how the M3 compares to M2 for quality of "macro" images.

I did take photos with the selection of close-up lenses, but I forgot to yank the memory card out of the M3 when I had to return the prototype housing.

 

[Interceptor121]

The maximum magnification without lens is when you get the camera at the closest focus point at the wide end. As both cameras focus at 5cm and the mark III has a wider lens the capture area is larger. Possibly in the 4" to one foot range the mark III out of the box can do better however you can out a +3 diopter on the mark I and achieve larger magnification. A +3 diopter would achieve nothing on the mark III as longer than the minimum focus distance at full zoom. At the end of the day the mark III will work but due to the shorter max focal length will require more powerful lens and getting even closer to the fish to full the frame. This can be a problem as some fish don't like you to be that close so in general is better to be further away than on top of the subject. Nevertheless thanks for the posts that are useful for people to compare

 

[coralgirl]

Interceptor, if i use the uwl 100 with dome (fisheyes) will it have vigneting at 24mm on mk3? And to get 1:1 magnification which diopter should i use? I am thinking of upgrading from rx100 1st gen to mk3. There is also canon g16 and gx1 mk2 that intrest me.

 

[Interceptor121]

I have not done a real test as I don't want to buy an ikelite housing based on past experience I would say yes at 24mm and eventually zooming this will stop hopefully at 28 however field of view will be less than the mark I or II at 28mm. I have written a post about upgrades. Personally I would not bother with any canon camera the image quality gap is too large. Once you leave the RX100 camp even moving to a micro 4:3 is not such a huge gap. The canon G series are definitely a big step back

---------- Post added July 14th, 2014 at 01:51 PM ----------

Also I estimate you need around +11 in water to achieve 1:1 this gives you a working distance of 7 cm from the lens once you take out the thickness of your close up lenses (for example 4 cm of two Inon) you are left with 3cm distance from top of the close up lens to subject
With the Mark I and II instead you were looking at 10 cm - thickness of the lens (sub see or UCL100) around 6.5 working distance to top of the lens

I think this makes it clear why the Mark III camera is not going to cut it for underwater photography

The closer focus distance becomes actually a disbenefit as it reduces the subject distance further and ends up possibly with the focus point inside the close up lens...

 

[coralgirl]

Thank you Interceptor

 

[insomniac]

The Inon UWL H100 works with the RX100M3.

With the Inon Dome Unit II on the UWL H100, it will vignette at full wide (24mm equiv), but a tap on the zoom lever to 28mm equiv eliminates that. I'll try to get pictures Monday.

No vignette with Ikelite W-30. This shot is at f/4. I did not have room in the sink for strobes, and since this was only a vignette test, I used a couple of Sola lights.

View attachment 188591,

Actually, according to Nauticam USA's facebook page (https://www.facebook.com/nauticam) there will be no vignetting when it's in their case and the camera is underwater. They stated above water there is slight vignetting that needs to be cropped in post, or the lens needs to be zoomed in slightly.

"With the UWL-H100, you can zoom all the way out when in water. On land it will show interference ("vignette"). The shot above of the boat on the horizon with whale shark in front, is a crop to deal with this, as it was shot above water. The other two shots there are at 24mm + UWL-H100. With no wet lens, you get no vignetting on land or u/w. With other w/a wet lenses, you may have to zoom in a bit."