Sony 16-50mm with extension tubes

[Hector1959]

I plan to buy an a6300 and I was thinking of giving a try to use extension tubes with Sony E PZ 16–50 mm to gain some macro capabilities. I want to "test my hands" before buying a more expensive macro lens (so far I've been using a G7X with a +6 wet diopter that gave me no more than 0.4x magnification but a strong macro lens would give higher magnifications harder to deal with).

I know the port should allow to this extended lenght and that I will lose the zooming since the ring would be deplaced.

This is something I could live with if doing macro. I could calculate before dive the focal length necesary for a certain magnification with a particular tube extension, but.... what would happen if camera turns off and lens collapses/closes?. Does this lens have a "memory" to engage in last focal lenght setting? or will it be set at a default setting?

regards

 

[Barmaglot]

I just tested it with my A6300 and 16-50mm; when the camera wakes up and the lens extends, it is always set to 16mm focal length, regardless of whether the camera was turned off manually or went to sleep due to inactivity timeout.

 

[Barmaglot]

Also, what port are you using? Keep in mind that if you're comparing specs, 16-50PZ quoted length (29.9mm) is in its collapsed state - it extends to almost double that when powered up, much like many compacts do, and most flat ports designed for it are made just barely long enough to accommodate its extended length (domes are, of course, another matter, but then you run into nodal point issues). The one exception that I know of is the SeaFrogs Salted Line bundled flat port - it's actually made to accommodate the slightly longer 10-18mm lens, so you'll be able to fit in a 10mm extension tube, and likely a 16mm one, though definitely not both.

 

[Hector1959]

Barmaglot,
Thanks for your reply.
I would like to point out that so far it is just a thoeretical exercise ahead of my very likely next buy, A6300 + Seafrogs housing.
For lens and ports to buy I am just seeing alternatives. And this is the reason of the questions posted.
For macro lens I have studied the Sony family. 30 mm is discarded because of the unpractical short Working distance. 50 mm was the prefered choice at first but inside the flat long port (FLP) I think WD would still be short and the use of my Inon +6 diopter may be unpractical. Another concern is that most reviews show that its weakness is that it takes long to focus (my eternal pain with the G7X)
Then I come to 90mm but besides its superiority in more comfortable WD, OSS, choices for supermacro, etc, it's said to be slow in focusing (don't know if better or worse than 50mm) and it is definitely an expensive lens.
So I "decide" (in the macro side) going step by step.
1) A6300 is a decision
2) Seafrogs salted line housing is a decision
3) macro lens seems to be either 50 mm or 90 mm but both need the flat long port, so this port is a decision.

It was then that came to my mind the idea of giving a try to extension tubes with the 16-50mm inside the FLP.
I am aware that this is not a better approach than dedicated macro lens but it will allow me time to study better which lens to buy, including other e-mount non-Sony ones. I was looking at Sigma 70mm but I calculate it won't fit in this port when extended.

I have never before shot truly macro, least supermacro. So, I wonder if I could manage to hold camera steady a these magnifications. Then, the extension tubes would be a cheap way to test my capabilities or train them.

Considering this FLP allows a macro 90mm which is 130mm long I calculate that a extended 16-50mm + extension tubes would fit. 26 mm for sure, may be double that lenght.

At 50 mm with 26 mm ET I wouln't even reach 1:1 magnification. I should set FL to 30 mm, or extend the tube.
At 16 mm with 16 mm ET I would have in theory about 1:1 but focusing distance at this magnication would be inside the port (!!!)
At 16 mm with 26 mm ET I would have 1.7x . Focusing distance would still be inside the port but I could place the camera farther and still have macro magnification (or near, need to calculate)

Increasing WD would need longer ET which at the same time would increase magnification (at MFD).

The problem with the focal length at which the lens would be set is not that much increased magnification since the difference between 16 and 50 mm would be less than 0.15x. My first concern is that the wide end of this lens is said to be too soft. I would have to deal with that and take it a compromise cost in my training.

But a new question arises. How would behave this lens + 26 mm ET's being far from the front glass of the port? Vignette? If so, solution would not be other than more ET's.

I would appreciate your comments about this.
best regards

 

[Barmaglot]

While 16-50mm might be able to work inside the flat long port (I just checked, it does not vignette at FLs longer than 45mm), I don't think that it will be a workable setup in practice. You have no way to zoom or manual focus, the autofocus will have to contend with extension tubes and with the port glass being dangerously close to its focusing range if not within it, every time the camera turns off, you have to open the housing and reset the zoom... it's just too much hassle. IMHO, a far more usable low-budget option would be the flat short macro port and your +6 diopter. You already have the diopter, and in this port, you can use it without any hacks that impair camera functionality - you can even get a wet wide lens to go with it and enjoy full flexibility; from a tiny goby to a whale shark on the same dive.

 

[Hector1959]

Barmaglot,
The short macro port is an option but I know I will buy later a macro lens 50 or 90 mm and I will need the long flat
port so I thought of a transitional solution using the FLP with the 16-50mm + ET´s. ( not expecting superb shots, just training at higher mags)
Short macro port will still be usable with a WWL por WA but my idea for WA is dedicated dry lens + dome.
I do not consider to open the housing and reset the zoom every time the camera turns off, so I have to stay at 16 mm.
My calculations with lens set at 16mm + 26 mm ET gives about 1,7x magnificaction but MFD would be inside de port (about 7cm)
I do not know how to calculate or estimate de focusing range. I know for Min FD, but I would need to know max FD to be sure that this would work. If Max FD is at least 300 mm it would be workable leaving about 150 mm in front of the port.
Other concerns would be vignetting. There would be an air space of about 50 mm between lens and glass port. I would need to calculate the angle of view of the new FD of 42 mm and the arc of that angle from back of lens to port glass to have an estimation.
So far I have just used a compact G7X underwater and a interchangeable lens camera means some kind of challenge.

 

[Barmaglot]

IMHO, you're overthinking it.

The short macro port costs $100. Looking at B&H, a set of Kenko tubes for E-mount is $129.90, Vello is $82.50. Neither will be of much use if and when you upgrade to a dedicated macro lens + long port, although you can retain the short port for dives where you expect to encounter a mix of macro and wide-angle. Vignetting in the long port at 16mm will be terrible - I'll post an example later, when I get home. The short port + diopter will be massively easier to use and will produce much better results, at a very similar cost.

As for compact vs ILC, with the kit lens + wet lenses, there is very little difference between how you would shoot the A6300 versus, say, an RX100. The housing is a bit bigger (but still nowhere near as huge as a typical DSLR, or even Olympus M43), your strobe sync speed is slower (price of an in-camera curtain shutter instead of an in-lens leaf shutter) and you need to stop down more for depth of field (f/8-f/11 rather than f/4-f/5.6), but that's about it. You don't have to use the viewfinder as you'd need on on a DSLR, you have a very similar zoom range, etc. Autofocus will be much faster than contrast-only compacts, but probably a little bit slower than PDAF in a DSLR.

 

[Hector1959]

Thanks. It's true. I am overthinking. I will follow your suggestions.
Happy New Year

 

[Barmaglot]

For the reference, this is what 16mm inside the long port looks like:

Granted, this is without extension tubes - I don't have any - but you get the idea.

 

[Hector1959]

Thanks. Good reference.