How to get really good magnification on super macro?

Hi,

I've been using my Nikon D7000 with a Nikkor 60mm macro lens in a Sea&Sea housing since 2013 and lately gotten more and more into super macro (hairy shrimps, skeleton shrimps etc.). I have two INON UCL-165 (screw on), but still have to crop more than I would like if I take a picture of something like a Costasiella kuroshimae (Sheep nudibranch) and the depth of field gets ridiculous. I'm wondering what kind of options I have in upgrading my system. Would it be wiser to go with

a) stronger wet lenses

b) teleconverter

c) extension tube

or do I have other options? What are the pros and cons? If I can get better magnification and better depth of field I'm prepared to invest in a 105mm lens and extra housing parts as well. I'd love to get some extra working distance between me and my subjects as with both wet lenses on the subject is pretty much attached to the glass. I've attached some pictures just to show my cropping issue even though the order became messed up (pic 1 and 3 are from the same picture).

Best Regards,

Vigfus

Hi Vigfus,

I find it helpful to think about optimizing macro photography in terms of resolution, magnification, and depth of field. Physics dictates that higher optical resolution automatically leads to less depth of field. So you can't have it both ways. But that only applies to the optical resolution. For instance, if you shoot 1:1 with the aperture wide open depth of field is razor thin and the optical resolution is very high. In fact it is much higher than the pixel size of the detector and much of the optical resolution is not captured while you still suffer from the loss of depth of field. What you really want is to balance the optical and sensor resolution so you don't loose more depth of field than is necessary. You could close the aperture to match optical and sensor resolution, gaining depth of field without losing resolution. Alternatively, you can increase the magnification so the smallest resolved features start to match the pixel size. In this case magnification actually helps in getting more detailed images, although depth of view will remain thin.

However, if the sensor resolution is already adequate then further increasing magnification will make the shooting a lot more challenging without really helping the image. In contrast it just means a loss in field of view, just like what happens when you crop in post. A typical situation is when you really close down the aperture to gain depth of view. By then you have lost so much resolution that increasing magnification isn't sensible in getting a more detailed image. There can still be reasons to do this. For instance to ensure that the subject is large enough in the view finder so you can actually make sure it is in focus.

The other point is working distance. The 105mm will help with that. In addition, the same wet diopter will give you more magnification on the 105mm than the 60mm. A teleconverter also gives more magnification without reducing working distance, but I would definitely prefer a 105mm over 60mm with teleconverter. If you are really into macro the 105mm will be a good investment.

Bart

The issue that you have is that the two diopters even stacked have focal length longer than your lens. You need as a starter a 105mm so that you increase distance and focal length to make the wet lenses work better. After that you can start looking at something like the nauticam smc if you are still not happy. The smc though is not much more powerful than the two Inon but has less optical aberrations

Thanks guys!

I've been looking at the 105mm lens as one of the investments to come so this makes the lens itself settled. I've heard that in some cases it makes a difference if you get an older or newer version of the lens. Is

Best Regards,

Vigfus