TG-6 Extra macro lens beneficial?

[Hector1959]

I think this would answer the question:

 

[tursiops]

In a Backscatter review of the TG-6 they suggest using the Bluewater +7 diopter. I really did not find the logic of this. I even so it was a mistake of their part maybe copy-pasting from another review of a different camera. Diopters do not magnify by themselves, they do it by allowing the camera focus closer. If TG-6 in supermacro AF (no need anymore to have the camera ein Microscope mode) can focus at 1 cm, there is no room to focus closer or gain "theoretically" any significant advantage for a few mm closer.

There are two separate issues: (1) how much magnification can you get? (2) how much stand-off distance can you get?
The problem with the TG-6 super macro modes is you get very little standoff, so firstly the lighting is difficult, and secondly the subjects get nervous. If a diopter (that is an IF) allows roughly the same magnification, but more stand-off distance, that can be beneficial.

 

[bvanant]

Nice video but it is not clear that you couldn't get as much magnification by zooming out a bit and using an external diopter in the non-microscope mode (not that you could easily light this). There are of course reasons to use an external diopter that aren't just adding magnification (better Bokeh for one) but in general I think it is clear that microscope mode is probably as good as you will need.
Bill

 

[Hector1959]

There are two separate issues: (1) how much magnification can you get? (2) how much stand-off distance can you get?
The problem with the TG-6 super macro modes is you get very little standoff, so firstly the lighting is difficult, and secondly the subjects get nervous. If a diopter (that is an IF) allows roughly the same magnification, but more stand-off distance, that can be beneficial.

As I understand it is the same issue, as they are related. With any lens the more you zoom in the more magnification, at any zoom, the closest you are from the subject the more magnification. But, every lens has a minimum focusing distance and it is there where diopters come into play but allowing getting closer to the subject, and therefore to achieve more magnification. You will not have more magnification on the TG-6 + diopters at 5 cm from subject than that achieved without diopters from same distance.
Let's put an example. You have a 50 mm lens that can focus at a minimum distance of 20 cm. You add a +5 diopters (200 mm focal lenght) and Focus a subject at 20cm. You won't have any extra magnification. The extra magnification begins when you get closer, and getting closer and Focus is only possible because of the diopter. That's the function of the diopter, enabling a lens focusing at a shorter distance, but if a lens is able to Focus at 1 cm a diopters would be useless.

Honestly, I wish I were wrong. I would like to have the same magnification a little farther than 1cm. I am just using optics theory. I lost my diopter and I can't try with my new TG-6.

 

[hilljo88]

With high magnification diopters you get razor thin depth of field. They are very hard to focus.

 

[bvanant]

Hector, you are mostly correct but a lot depends on the wet diopter. For example the Sony Rx100 has a min focus distance of 40 mm and an image size of 75 mm. With the CMC you get a min focus distance of 65 mm and a 3x magnification. So it can be done. I don't have a TG to play with, but might borrow one and see how it might work with one of the many external diopters I have. As for DOF, that is where you can't beat physics.

Cheers
BVA

 

[tursiops]

As for DOF, that is where you can't beat physics.

Part of the physics is the dof relative to the sensor size, or equivalently the lens focal length. The TG6 sensor is so small that the (say) f/2.8 dof is much greater than for the same f-stop and magnification on a larger sensor, like a FF DSLR or even a m4/3 sensor.

 

[bvanant]

Sure that is true and why it is harder to get out of focus backgrounds with MFT compared to say full frame. That being said, closer shooting and high magnification generally mean less DOF independent of the platform.
Bill

 

[tursiops]

Sure that is true and why it is harder to get out of focus backgrounds with MFT compared to say full frame. That being said, closer shooting and high magnification generally mean less DOF independent of the platform.
Bill

I was actually responding to hilljo88.

 

[Hector1959]

Hector, you are mostly correct but a lot depends on the wet diopter. For example the Sony Rx100 has a min focus distance of 40 mm and an image size of 75 mm. With the CMC you get a min focus distance of 65 mm and a 3x magnification. So it can be done. I don't have a TG to play with, but might borrow one and see how it might work with one of the many external diopters I have. As for DOF, that is where you can't beat physics.

Cheers
BVA

As I said I would wish to be wrong. The only diopter I have usted is the Inon UCL 165. Unfortunaly I lost it. But after buying the TG-6 I stopped the inmediate plans to replace it.
I had a Canon G7X which has same sensor than your RX.
Your numbers with the CMC are amazing. 3x magnification would mean that you can fill the frame width with a subject of less than 5 mm. 5 mm against 75 mm without the CMC is an amazing difference.
Regards