We have had a discussion about the appropriateness of lens hoods for these 100mm macro lenses. I said that I would run a quick experiment to see if a more appropriate lens hood could be used for shade and protection.
I made the observation that the D-FA hood does not move with the inner lens barrel. This leaves only 5mm of lens hood to shape and protect the front element of the lens at closest focus. The front element of that lens is recessed only a paltry 15mm. This gives only 20mm of shade and protection to the lens. This compares poorly with its Takumar ancestor with a front element recess of 20mm and a factory lens hood of 49mm for a total of 69mm of shade and protection at any focus position.
Two sets of tests were made. The first a high light angle of 60*, with a 75mm hood and also a 49mm hood. The second set of tests is based on a moderate light angle of 45*.
The first image is that of the lens mounted on a K5 with the closest lens focus set and the camera placed at that distance. This was confirmed by a live view check. The red object placed centered beneath the lens is the same size as the camera's APS sensor.
The second photo shows the lens, red target object, 49mm lens hood and a 30-60-90 drafting triangle with a blue color on the hypotenuse side. That blue color represents the light ray closest to the edge of the hood. With the 49mm hood, that light ray falls across and beyond the target area as indicated by the blue line covering the entirety of where red object touches the white paper underneath. This shows that the 49mm hood is the right size or too short.
The third photo shows the lens, red target object, 75mm lens hood and a 30-60-90 drafting triangle with a blue color on the hypotenuse side. That blue color represents the light ray closest to the edge of the hood. With the 75mm hood, that light ray falls just short of illuminating the target area as indicated by a portion of the red object touching the white paper underneath, not hidden by the blue triangle edge. Notice that you can seen where 2-3mm of the bottom of the red object and white paper interface. About 17mm of that object/white paper interface is covered. This shows that the 75mm hood is just barely too long.
I have not posted the photos for the 45* moderate angle light ray. If the 60* light ray clears or barely misses clearing the shallower 45* ray will easily clear.
The 49mm hood is the factory dedicated one for the Takumar 100mm macro. The 75mm lens shade is the one dedicated to the Takumar 200mm f 5.6 lens.
These tests are for APSc only.