[biesnitz]

I have had my K-r for a while and enjoyed playing with all the features - I am at best an interested amateur. Recently I got involved in macro photography for which I bought a used Sigma 50mm 1:2.8. DG macro lens which worked nicely, and the transfer of the pictures via UBS cable to my iPhoto app was no problem. Then I bought an old Pentax 50mm 1:2.8 macro lens and attached it to the K-r and my copy stand to take some pics for a comparison with the Sigma lens. First, although I thought that the optics of both lenses are very similar, I could not get a full frame picture with the Pentax. The images were sharp but small. Then I tried to load the pictures onto my Mac with the same USB cable I had successfully used so far, but nothing doing. There was no evidence that the camera was connected to the computer, no additional device symbol, or camera screen with instructions. As I am using a multiple hub that takes 4 USB cables I switched the cables around, but to no avail.
I suspect that in attaching the manual Pentax macro lens I must have touched a setting, or done something else inadvertently. Has anyone had a similar experience or can guess what is going on? I would appeciate help.
Thanks,
Biesnitz

[boriscleto]

It could be a bad USB cable, or the USB port itself may have become damaged.

Get a USB card reader. Don't pay more than about $10.

Meritline sell one for $2 with free shipping.

SD Card Readers, Micro SD Card Readers | Meritline.com

[biesnitz]

Hello, Boriscleto,

you put your finger right on it. I did not go far enough checking the connexions. Now I just plugged the Pentax USB cable directly into the Mac, and sure enough, the loading started and was completed. Then I chucked out the old hub and replaced it with a new one from my bottomless collection of accessories.

Thanks for the trouble shooting,
Biesnitz

[biesnitz]

I know it's bad form to answer one's own questions, but I am new to the Forum and did just now chance upon the great reviews of older lenses. Here I found that my Sigma and the Pentax lenses are not optically alike. TheSigma has a 1:1, the Pentax a 0.5 magnification, i.e. with the latter I have to use extension tubes to get to 1:1.-- 1:1 would be easier for people with bad eyesight, but one can examine the image on the camera screen with a loupe and make focus adjustments accordingly.

Biesnitz