Portra 800 turns night into a day

Film image taken with Minolta MC Rokkor-PF 58 f1.4.

Classic 58 mm Minolta legacy lens and Kodak Portra 800 captured this early summer morning in June.

This lens and film combination offers good opportunities for photography in low light. The 58 mm Rokkor is fairly sharp already at f3.5 whereas some other lenses need to be stopped down to f5.6 for comparable sharpness. Together with ISO 800 film there are more than three f-stops more exposure available for hand held photography. This means that photography does not have to end at sunset but continues all the way to sunrise.

If there is one word to describe the 58 mm f1.4 Rokkor it would be 'awesome'. Lenses are still available on auction site for relatively low prices, although several copies had to be obtained to have one mostly working sample. Common issues are stiff focus ring and slow and oily aperture blades. Both issues can be solved in many cases.

For summer 2018 photography season - well underway by now - the theme is photography in low light with Kodak Portra 800 and 58 mm Rokkor-PF.

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Concept for solar booster

Small low cost solar panels have high initial voltage but drop to their knees as soon as the smallest workload is placed on their shoulders. The panel in the image has 6 Volts in bright sunlight but could not make a 5 Volt led even blink.

The only load useful to a solar panel is a capacitor. The capacitor in the image quickly charges to 6 Volts from the panel. Now the 5 Volt led shines brightly for a few seconds when fed from the capacitor.

The ingenious solution is two alternating capacitors - one charges to 6 Volts while the other one discharges at 5 Volts. What is needed is a circuit that constantly switches between capacitors.

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Shutter and lens mount for Rokkorcam

Altissa Altix camera appears to be the perfect platform for prototyping new Rokkorcam film camera. In the image Tempor leaf shutter can be seen. Mechanical shutter needs no batteries and is positioned correctly in the light path so that Rokkor lenses can be rather easily adapted and tested.

Rather than adapting lens the Altix camera lens mount will be replaced with M42 thread mount. The result depends on the shutter diameter - if it allowed wider than SLR images go through to 45 mm wide film frame.

Can you already see a Rokkor on top of the camera like I do?

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Developing in July

Summer 2018 photography season has started. Website updates will be slow for the next several weeks. Many product prototypes in various stages of development.

Products and services in development (in order of priority)

Rokkorcam - a new film camera system taking 45 mm wide 16:9 aspect ratio images on standard 135 film
Optical film scanning workbench
Pentax-110 m4/3 adapter with fixed iris
M42 thread mount conversion for Minolta MC Rokkor-PF 58 f1.4
M42 thread mount and Konica AR mount conversion for several Minolta Rokkor lenses
Service and restoration for Minolta MD zoom lenses

Completed products

Minolta-Konica conversion for MD 35-70 f3.5 Macro zoom
Adapter for using Minolta MD 35-70 f3.5 Macro zoom lens with Canon EOS cameras
Restoration of Minolta MC W.Rokkor-SI 28 f2.5 wide angle lens
Manual aperture modification for Vivitar 35ES (Revue 400 SE) pocket rangefinder enabling battery free operation
Fixing Tokina RMC 28 f2.8 stuck iris

Recent articles

  Best from previous seasons (winter 2013-2014) - MC W.Rokkor-HH 35 f1.8 scanned with 5D (film)..

 Making slides from color negative..

  Adapting 5D (digital)..

  Best from last season (summer 2017) - Red dawn with Hexanon AR 40 f1.8 (film)..

  Lens test - Pentax Super-Multi-Coated Takumar 28 f3.5 versus Minolta MC W.Rokkor-SI 28 f2.5 (film)..

  Best from this season (winter 2017-2018) - Minolta-Konica sample image (film)..

  Best from this season (winter 2017-2018) - Hibernating boat with MC Tele Rokkor-PF 100 f2.5 (film)..

Support Film color grading tutorial - adjust shadow saturation..

 Minolta MC Tele Rokkor-PF 100 f2.5 - Lens technical data and sample film image..

  What others shoot - Primotar (flickr)..

  Best from last season (summer 2017) - Bird in sunrise with Hexanon AR 40 f1.8 (film)..

  Best from last season (summer 2017) - Easy to adapt Tokina RMC 28 f2.8 wide angle lens (digital)..

  Best from last season (summer 2017) - Serviced Tokina RMC 28 f2.8 on Canon 5D full frame (digital)..

  Best from last season (summer 2017) - Bad sky day with Vivitar 35ES pocket rangefinder (film)..

  Best from previous seasons (summer 2016) - Spontaneous photography with Vivitar 35ES pocket rangefinder (film)..

  Best from previous seasons (summer 2016) - Action photography with a manual tele lens (film)..

What is Rokkorlab

Rokkorlab is a not-for-profit 3rd sector association for development of photographic and other fine mechanical products and services. A new product or service is first invented and proposed. If there was demand for the product, resources could be pooled to develop prototypes. Finished products could be manufactured on demand and made available to contributing developers. Suitable products could become available for buyers.

3rd sector means independent - the association is not tied to a commercial or other entity. Ideas flow freely. Several technology platforms are in development for prototyping and manufacturing

Are you a developer

Developers often struggle to find the necessary support to create entirely new or improved products. First there must exist an idea. But what then? How to begin to push the idea into a real useful item? This is where a developers' association could enter the picture.

If interested in products or product development, please use contact information