Thursday, June 23, 2022

The Pergear Lens Goeth (Outside)


We'll I've managed to experiment a tiny bit with the Pergear fisheye lens, and it's been fun. It's actually has a close focusing distance of 0.3 meter, so by using a precision guess, I simply hold the camera about one foot from my eyeball and can be assured of a reasonably sharp image by "toy lens" standards. That fixed F 8.0 aperture gives me quite a bit of leeway, but can cause some problems when trying to establish proper exposure. 

As you can see I mounted the lens on a simple Fuji X-E1 body and mounted a powerful Flashpoint manually controlled speedlight in the hotshoe. To determine a workable exposure solution, I had to access the fixed and variable settings I had to work with.
  • Aperture: F 8.0
  • Exposure Time: 1/125 second minimum for a clean edge to edge flash exposure.
The variables I could control included:
  • ISO Setting (100)
  • Flash Output (full)
  • Flash Distance (whatever gives the best results)
Background Exposure: With my physical settings of F 8.0 and 1/125 of a second, my only option was to decrease the ISO setting to its lowest setting, which was 100. Based on the "Sunny Sixteen Rule", the sunlit background should be overexposed by one and two thirds of an F-stop, but judging from my selfie, the background exposure appears spot-on.

Foreground Exposure: Since flash automation isn't available with these fully manual lenses, the exposure had to be regulated using flash-to-subject distance to increase or decrease the exposure. I rotated the flash head so that I could bounce the light off of a convenient white wall, and set it to full power. To regulate the exposure, I moved the camera closer or farther from the wall depending on the effect I was trying to achieve. This is more of a trial-and-error approach because the Inverse Square Law doesn't fully apply to bounce flash. Trust me when I say that reducing the output is much easier than increasing it, which is why I started with Full Power and slowly decreased the output by moving the flash/camera farther from my bounce-wall.


The resulting photo shows some of the shortcomings of using this lens for anything serious, but there are some take-aways:
  • If the lens is centered on the subject, curvature can be kept to a minimum so long as straight lines are kept away from the far edges of the frame.
  • Facial features are subject to some distortion due to the ultra-short (one-foot) working distance.
  • Light fall-off from the bounce flash can be significant, as demonstrated by my hand. At this distance, small changes can have a huge impact.
  • Cropping to a square format eliminates most of the troublesome edge curvature.
  • If I wanted to lighten the background, I could have increased the ISO setting to 200 and decreased the flash output by one-half, or chosen a Fuji body with a 1/250 flash synchronization speed.
In the end, this lens did exactly what I had hoped it would, It's close focusing distance makes it more versatile than the Fuji pancake. I look forward to a long morning walk with my new Muse Of The Day.

Postscript: The underexposure of my right hand was probably due to the small size of the bounce surface when the flash/camera was held so close to the wall. Had I held my glasses closer to my face, the exposure would have been more even.