[someasiancameraguy]

Looking to build a set of primes for video work since weight and size advantages do well for gimbals:

1. Low focus breathing
2. Relatively neutral rendering for a consistent look over the lens range. Can't have too many distracting elements like CA (esp LoCA), super swirly bokeh, etc.
3. Nothing too rare/expensive
4. F 2.8 or faster with usable midframe sharpness wide open (corner of aps-c/super 35)

My goal is to have a set of primes that I can use for both my Pentax cameras as well as adapt to other cameras for video (aps-c/super 35).

Any suggestions?

[UncleVanya]

Before we get too deep, what other cameras would you be adapting to? I assume mirrorless?

To be honest I rarely pay attention to focus breathing except in zooms. I’ll assume these will be mostly manual focus lenses since screwdrive is loud in video and fewer primes that aren’t fairly new have lens motors.

[someasiancameraguy]

Before we get too deep, what other cameras would you be adapting to? I assume mirrorless?

To be honest I rarely pay attention to focus breathing except in zooms. I’ll assume these will be mostly manual focus lenses since screwdrive is loud in video and fewer primes that aren’t fairly new have lens motors.

Fuji X series and maybe Sony FF. Gimbals are the Zhiyun Weebill-S and DJI RS2 with follow focus systems on both. Screwdrive lenses are only somewhat usable with external mics and slower focus pulls.

[stevebrot]

A general rule of thumb is that, aside from specialized cinema optics, all lenses should be assumed to exhibit focus breathing (FOV varies by focus distance). Whether it be positive (FOV narrows), the common variety for block focus lenses, or negative (FOV widens), the internal focus variety, depends on lens design.

To the best of my knowledge, no K-mount prime has a reputation of being free of focus breathing. As for your other requirements...the lens sample photo archive might be helpful.

https://www.pentaxforums.com/forums/130-lens-sample-photo-archive/


Steve