Macro set up #2: Olympus E-M1 + Panasonic 35-100 + Canon 250D close up lens

This set-up is similar to the one used for the flower photos in the previous post and which is shown two posts-ago here.  But instead of using the 500D closeup lens designed to focus a zoom lens at 50cm (about 20"), the 250D is designed to focus a zoom lens at 25cm (about 10").

The 250D is slightly thicker, perhaps because of its
greater magnification. More magnification = more glass.

Olympus E-M1 plus Panasonic 35-100mm plus Canon 250D close-up lens

This is what I found out on the Panasonic 35-100:

The advantage of the 250D is increased magnification. Assuming the lens is all the way zoomed in at 100mm (FF=200mm), by cutting the focusing distance to 10", the 250D gives close to a 1:1 macro (FF equivalent). The 500D  can only give you about a 1:2 macro (FF equivalent).

But with greater magnification comes decreased depth of field.  The depth of field with the 250D is so thin that I found it necessary to use F5.6 or F8, whereas with the 500D I used F2.8 or F4.

Depth of field at F2.8 and 100mm (FF 200mm) = Perhaps 1/2".

Depth of field at F8 and 100mm (FF 200mm) = Perhaps 3/4".
But with more gradual fall off giving the appearance of much more DOF.

Regardless of the one you use, or with any other acromatic lens for that matter, it takes some getting used to.  Your lens will not focus at infinity!  The 10" and 20" focusing distances are not minimum focusing distances, they are essentially the focusing distance.  That is why they work best on a zoom.  To widen your composition you can't move further back more than a few inches from the subject. Instead, you need keep the same focusing distance and zoom out.

Zoomed in at 100mm (FF 200mm)

Zoomed out at 35mm (FF 70mm)

The photos below were all taken with the 250D.  However, for flower photography I prefer the greater working distance of the 500D.  With less magnification, the depth of field is greater, and I can consequently use a bigger aperture thereby allowing more light to enter the lens.  The more light entering the lens, the lower the ISO required and/or the faster the shutter speed, both of which are good things.  Also, the 500D seems to be more forgiving when it comes to focusing distance.  The sweet spot is 20", but it seems I can go a couple of inches more or less than 20" and still lock focus.

Zoomed back to 65mm.  F8

At 100mm.  F8

At 100mm. F8

At 100mm. F8

80mm. F4

35mm. F2.8