Minolta RD 175 - Retro Review
The Minolta RD 175 (1995) is the oldest working digital modified film SLR I have managed to find so far.
Minolta RD 175 & AF 35-70mm f/4 lens
(Taken with the Sony A9 + Tamron 90mm f/2.8 Macro)
Specifications
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Lens Mount:
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Resolution:
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ADC Depth:
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Sensor:
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Crop:
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Viewfinder:
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Shutter:
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Startup (s):
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Flash Sync:
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AF System:
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AF Points:
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Sensitivity:
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Burst (fps):
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Buffer:
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LCD:
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Memory:
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Data Cable:
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Battery:
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Weight:
Minolta AF
3x 0.38mp
8bit
4.8 x 6.4mm CCD (x3)
2x
90%, 1.04x
1/2 sec - 1/2,000th
2
1/90th
PDAF
1
800
0.5
4
None
PCMCIA type III
SCSI-2
7.2v 1200mAh Li-ion
1.1Kg
History
Coming to small market of digital modified film SLRs, pioneered by Kodak in 1991; The Minolta RD 175 Initially released only to professionals. Selling for $10,000, in 1995 it aimed to undercut Kodak's pricing. It was developed in conjunction with Agfa, who called their identical camera the "ActionCam" (which launched a year later).
Build
Based on a Minolta Dynax 500si Super film camera. Not exactly a high end digital machine. The clumsily bolted on back and bottom feel very poor & plasticy considering its price.
Image Quality
As the text on the front suggests; It has three separate 0.38 megapixel CCD sensors. Light was split through a prism to each of the three sensors. Two of which were purely for green and the final one shared red and blue (in an interlaced style array). This made 66% of the photosites for green (up from the usual 50% with common beyer pattern sensors) and only 1/6th of them for each of the other two colours. Humans are more sensitive to green, but this was probably pushing things too far. The final resolution was then interpolated up to 1.75 megapixels (from 1.1)
Like Nikon's E2 Digital camera, the RD 175 used reduction optics to refocus the light on to a much smaller sensor (or sensors in this case), but where the Nikon did that from a full (35mm) frame, the Minolta suffers a heavy 2x crop. Because of this system, just like Nikon, the Minolta has a limit on the minimum aperture. f/6.7 is as low as you can go here (regardless of what lens you use).
There are several reasons why the image quality of the RD 175 is poor compared to other film based digital cameras of the time, like the Kodak DCS 420. These are:
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Having different sensors for each colour can lead to more alignment issues than normals
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Small CCD image sensors
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Reduction optics requires adding more glass between the lens and sensor
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RAW files are no longer supported in any software
Speed
The startup time for the camera With a burst speed of up to 0.5fps (that's 1 frame every two seconds) this is in no way an action, or sports camera. Auto focus is pretty slow and with only a single large focus area it's not the most reliable, low light conditions being especially poor.
Hardware
The RD 175 was commonly used with a 131MB PCMCIA card, which could store 141 images. If you don't have one of these and can't find one, you can also use a PCMCIA adapter for Compact Flash cards. Cards traditionally needed to be formatted inside the camera while it was connected to a computer via the SCSI-2 connector, which can be difficult 26 years later, even if you do have the cable. The alternative option is to find an image of the formatted card, which you can burn to the card.
Each part of the camera required different power. A 2CR5 battery for the film camera, a 1200mAh rechargeable for the digital elements and a C2025 (watch) battery for the clock, to attach the correct date to the files. Surprisingly mine came with two original rechargeable batteries which both seem to charge and work fine, which is lucky as I don't think you can find them any more.
This camera has no rear screen, thus to change any of the digital settings (including the date) it also required connecting it to a computer via the SCSI cable.
Buying Used
Being 26 years old the RD 175 is one of the oldest digital SLRs around, but it's not a particularly rare camera. Along with the Agfa ActionCam they are pretty easy to find on Ebay. If you want to get one of these to actually use it I recommend caution, unless you enjoy a challenge and/or already have an old PC with a SCSI-2 interface. I would still try to make sure to find one with as many of the
Final Thoughts
Being only four years into the digital SLR story, cameras like the RD 175 are an interesting piece of history. They may not be the prettiest thing to put on display, or the most enjoyable cameras to shoot with, but they do still work... for now.
They can already be extremely difficult to get working. I had to enlist help from several people online to get mine able to spit out images that I could see on a Windows PC. Computer compatibility diminishes all the time, but the bigger issue as time goes on is the batteries. It won't be too long until these rechargeables no longer hold a charge and there are no replacements any more (official or otherwise). This problem is vastly accelerated by the obscurity of models like this. Iconic cameras like the Nikon D1 will probably function for another couple of decades or so, but it's a miracle that this Minolta still works.