SMC Pentax-M 100mm f4 macro

I’ve had this lens for years but never really used it apart from for the odd indoors figure shot. With spring rapidly approaching there is an abundance of flowers & blossoms lining my path to the lab every morning (dissertation deadline is looming, so every day is a lab day even in the current ‘holiday’) so what better subject for macro shooting? I need to do a more scientific test comparing the performance at different apertures, but all of these were at 5.6 & I’m already getting a feeling of what this glass is capable of.

I’ve noticed a little bit of CA, but I’ll need to do more testing to see how bad it can actually get.

These were all shot on my K20D, which has a 1.54x crop sensor & I cropped this shot down quite a bit in Lightroom as well, but it still has plenty of detail.

A 100% crop of the above.

Definitely my favorite from this morning’s walk, the flower on the right is tack sharp. This one is cropped down even more than the last one, I cut out maybe as much as 40% of the frame.

Once again a 100% crop for you to peep at.

2 thoughts on “SMC Pentax-M 100mm f4 macro”

  1. I have not seen a bad photo of this lens yet, and yours is so sharp and full of colour, I have a chance at buying one, but I am a unsure if I can get it to work on a Sony Alpha mount? any advice would be appreciated.

    1. Sorry for not responding sooner, I expect you have already found some advice? If you haven’t, then because the flange distance of the Sony Alpha mount is less than that of the Pentax K mount, you can indeed mount Pentax K lenses onto a Sony Alpha via an appropriate adapter. A quick search on eBay however shows that these adapters are of the optical type – eg they are not simply a hollow metal adapter but they have a correcting glass optic. Because of this the image quality you get is dependent largely upon the quality of the optic in the adapter, so it is worth buying a more expensive one rather than the cheapest one you can find.

Leave a Reply to Dave B Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.