Rx100v with cmc-1 focus image

Hi! I have a rx100v ikelite setup and use the nauticam cmc-1 for macro photography. One area that frustrates me is that most of my viewfinder isn’t the subject and I have to guess if the image is in focus when I take it. If I zoom in, the image won’t focus at all. Is there a way for me to make the viewfinder show the subject closer so I can determine that I am in focus?

Judging by the vignetting in your example, it looks like you're using the close-up lens while the camera is zoomed out. This is not the right way to do it - you should be zoomed in all the way to 70mm. If the camera doesn't focus, this means you need to get either further away from the subject, or closer - most likely the latter. Your working distance with CMC-1 is 55-75mm; it will not focus outside that distance range. Note that CMC-1 is a fairly strong close-up lens; at the closest working distance, your subject size is 35x23mm. A CMC-2 will let you stand somewhat further away, with a working distance of 80-124mm, and smallest subject size of 48x32mm.

Thanks for the response! With the cmc-1, I haven’t been able to focus on anything at all at full zoom. I can’t get any closer to the subject either because I’m like a mm away from it from the wet lenses. I’m trying to determine if this is a limitation of the rx100v setup. 

In that case you're too close. Per Nauticam's port chart, the working distance of CMC-1 on RX100V is 55-75mm - this means that you have to be no further away than 75mm (3 inches), and no closer than 55mm (5.2 inches), giving you just 2cm (0.8 inches) worth of working distance range.

Ok. So I should try zooming out completely and moving back from the subject so that it appears larger on my viewfinder. Or try getting a cmc-2. 

No, zoom in completely and practice in a bathtub, or kitchen sink, or whatever, until you get the feel of proper distance between camera and subject. You can try setting your lens to manual focus, turning it to closest focus distance, then moving the camera in and out until the subject is in focus. If, however, the subjects that you typically shoot are larger than what CMC-1 affords you (approximately 45mm across), then you will need the weaker CMC-2.

Yes you want to zoom in completely - I would initially ignore where you are focused, then move in until you can recognise the subject on the screen  Now slow down and rock back and forth over the point of sharpest detail and take the shot when it is right.   Probably work best in manual focus.  The camera probably has a focus peaking setting which might also help determine the point of sharpest focus you might want to try.

also a focus light is very helpful when you are learning, as you are likely depending on a lot of help from autofocus.

Is a focus light different from a ysD2j?

A focus light is a seperate light to give you enough light so AF can work well.  While it may help eventually , I would suggest Auto focus may not be a huge amount of help to you until you master the correct technique.

The problem you have is that the working range is very limited.  If you try to rely on AF and you are not inside this very limited range AF won't help you at all as it won't find anything to focus on.  So you need a proper routine to get the camera in the right range.  You have to be very stable in the water to stay in this range.  If you fall outside the range nothing will be in focus. 

MF is probably the best option - at closest focus of the lens the point in focus is 55mm from the end of the diopter and at infinity focus the point in focus is 75mm from the end of the diopter.  At closest setting the area covered will be 35 x 23mm.   As I described slowly move in until you can see your subject and rock back and forth till it's properly focused and take the shot. 

You can try AF but you still have to slowly move the camera into the correct position watching the screen till it comes into focus - wait and do not  try to AF till you can clearly see the subject.  If you hit AF early it will just hunt.  I'm not sure what AF is like with diopters on a RX100V but it's likely to be slow.