Thanks Henry is right with K (Exponent MTF) you can influence the response of the sensor and should be calibrated on the type of camera used. In the previous comparison I used K = 3 but with my measurements made on Canon 5D, 5Dmk2, 40D and Sony NEX-7 I get better agreement with K = 4. Below is a com...

http://www.photomacrography.net/forum/userpix/4359_fig_1_2.jpg Hi, this is program I use to decide on the conditions for recovery stacking sequences The first version was limited to calculate only the DoF and aperture, then, to understand how these parameters affect the response of optics in the ne...

I have found found that when testing macro lenses and microscope objectives using a slanted-edge target, a high quality chrome on glass photomask [e.g. an Edmund Optics chrome on glass MTF slide] gives higher MTF values than a blackened razor, which is consistent with what might be expected from th...

Does this mean in practice that one should aim to use F4 on an MPE-65 lens by preference ( assuming other requirements such as DOF or minimum light do not apply ) as this is the point where the MTF is at a maximum for this lens? Do you have a description of your setup using the smoked razor blade, ...

Hi, The curiosity to evaluate the efficiency of my equipment macro led me to write a program based on the method Slanted-edge. Here a good description of the method: http://dougkerr.net/Pumpkin/articles/MTF_Slant_Edge.pdf http://www.photomacrography.net/forum/userpix/4359_prog_1.jpg I was pleasantly...

Saul, Delightful image! I particularly like the structural color you recorded in the wing. :D Like you, I find it cool that Andrea Hallgass has written a slabbing utility and freely shared it, as have I (SlabberJockey) and several other authors of free slabbing utilities that work with Zerene Stack...

Rik, I agree with you that the CoC_tot is a value that depends on the method by which it is calculated, but I give it only a relative importance, I consider it only a useful parameter to determine the initial conditions on the basis of sensor camera cutoff frequency . If we consider the graph OTF ba...

Thanks Rik for your detailed reply that stimulated me to do some checking, but I'm not having your theoretical knowledge on the subject so I have to settle for empirical evidence. I wanted to see how varied the resolution in lp / mm at different OTF 25% 50% 75% versus the ratio CoC_DefocusOnly / Air...

Hi Rik, I follow from lot of time this forum where I learned many things but my poor knowledge of English does not allow me an active participation. I use the OTF diagrams to determine the step length in Focus Stacking and for this purpose I have written my calculator; this calculator allows you to ...