Month: October 2019

Minolta SR-2 vs SR-1 comparison

peter 22/10/2019 No Comments

Ever wondered what the real internal differences are between Minolta‘s first SLRs? First pic is of an SR-2 stripped of the ‘leather’, top and bottom plates off and my high-tech protection for the mirror box internals. The front plate with the mount and self-timer has not yet been removed.

SR-1 partially dismantled, but with the front mount section already off and the self-timer no longer fitted. Notice the difference between the castings and the ‘SRC’ in relief on the front next the mount: on the SR-2 there is not any such marking.

Here I’ll give a short look inside to still your curiosity (and mine!). So the SR-2 was the first in late 1958 and is put next to an SR-1 from around 1961, the ‘c’-version; the last one before the change was made to the aperture automatic. Two quite different mechanicals altogether, despite looking very similar, especially the bottom end, where the aperture and shutter actuation takes place.

Optically, the early and later models are relatively easy to tell apart if you know what to look for.. all the 1959 models have a much smaller eyepiece on the back, which is not so easy to spot at a glance. Easier to notice is the shutter-speed knob on the really early ones (the SR-1, too) that needed to be lifted to change the shutter-speed. On the top the scale is not quite evenly distributed, the 250, 500 and 1000 look evenly spaced, but they do have a little white line engraved to show the actual position needed to dial in those three speeds. From the front, the early dial is more conical in shape, wider at the bottom and smaller in diameter on the top than the later model (there is about a 2mm gap to the winder-lever). The later one, as you can see, is more straight from the side, and is as a result larger on top and has evenly spaced engravings up to 500, without the extra lines. The earliest SR-1 shutter-speed dial was similar in shape and size to the SE-2, missing the top speed, of course. There follows a series of photos showing some of the the external and the internal differences. Later I will show the internals of the first SR-1 model, but the differences between these two models are more obvious 🙂 The picture below shows the SRC on the casting rather more plainly.

There are, of course, lots of detail differences, that are too many to mention here, but worth mentioning and visible in this shot, is the mirror-fixing with screws, rather than the riveted-on mirror in the SR-2 🙂 There are also subtle differences between the self-timers, not only the front casting which they are mounted to: The one on the bottom or the right in this picture is off the SR-2 and fits behind the oblong brass plate. It also has an extra large flat screw (taken off on this picture below, but visible later once mounted) on the front side and the teeth on the spring-gear (the largest one) look like they have been ground or worn down… look closely at the pictures and you will see what I mean! The difference in the gear is plain to see.

SR-2 with the sellotape and here the differences in the gear-teeth are more obvious on this one. Note also that the backing plates are not the same, though the mechanisms are largely interchangeable:

Here the SR-2 self-timer is fitted and the large screw which is no longer on the later models at the front is rather obvious. The screw behind it on later ones is also significantly thicker (see pictures above).


Below shows the shutter-release mechanism in the base which is distributed half-half between topside and bottom. Most jamming can/must be sorted down here, the shutter speeds are controlled on topside. The lead-wires are for the flash synch and every camera seems to have them differently routed, depending on the wishes of the assembler! Here the difference in the size and shape of the tripod-mount is also visible, along with the completely different mechanical layout… few interchangeable parts here!

A look at the base plates shows that both are also different, as the mechanism on the SR-1 needs a cut-out at front (behind the lens-mount) to accommodate it – in preparation for the following model. At this stage, they both still have the long-travel aperture lever. the hole for the tripod-thread is also larger on the baseplate of the later body.

Well, that wraps it up for today. I will sort out the orientation of the pictures when I get home… I wrote this on my phone and it won’t let me do everything I want to!

Early Minolta Auto Rokkor-QE 1:3.5 f=100mm comparison

peter 09/10/2019 No Comments

How interesting it is to get two lenses like this next to one another to compare, made only a few years apart. The two in question are probably the most underestimated in Minolta’s lineup for very many years and still perform very well even against modern lenses at 43MP… These are just as sharp, if not better, certainly in the edge resolution than the 2.5 and the 100mm 2.0 that is in high demand (only because it is rare, not for its performance).  I might  go into that in more detail later, around when I release a test of the 24mm VFC 2.8, how to use it to do what it does, what VFC is actually useful for and some ideas about lens-testing methods in general, including inherent non-flat focus field (curvature) in lenses in general – which is always taken as given.

So, to start off with, looking at the fronts, I have two 100mm, 3.5 lenses from Minolta, built only a few years apart. The early one, an ARI, ser 1201946. Looking at many lenses, I might conclude that this is a lens of series code 12, number 01946 produced? There are many theories about the Minolta serial numbers and any of them could be right or wrong in the absence of any proof 🙂 Made somewhere in 1959-60. Whatever, the front engraving is as expected. The second one, an ARII with the serial 1213805  is missing the expected ‘Lens made in Japan’ engraving on the front, so is one of the earlier ones of this series produced.

If you look closely, you will also see that the front lens is more deeply recessed into the front on the later model.

Now turning to the back, we can see more differences: ARI-typical closed ring and screwed-on aperture link, ARII-typical linkage poking out of a slot in the back and, of course the stop-down lever now necessary after the automatic diaphragm was introduced on the SR-1 (4th model) and the second run of the SR-3, meaning that after the exposure, the aperture opened immediately. Yes, the knurled ring is missing on the stop-down lever, but will be added when I get one in 🙂

Also note the relative position of the rear lens elements, both focussed at infinity in this picture.

Here shown at an angle to emphasise the differences between the two, the ARI sits considerably deeper, which makes me wonder about them being the same formula for lenses and groupings…

Now both are focussed as close as can be done, 1.2m and 4ft, ARI Stil much deeper.

Interesting how both are so different internally, obvious from the back. Look how the shrouding goes right in to cover the full depth of the travel of the rear element here on the ARII…

… Whereby here the thread of the focus ring is exposed when wound to close-focus!

Now take a look at the difference in size between them: First the length is obvious. The added length of the later one (here on the left) seems to have mostly been added on to the front of the focus-ring :). Just also take note of the difference in the thickness of the focus-ring (which is why there is a bigger step in the front of the barrel of the earlier lens).

Here the nice even engravings are obvious (except for the ‘4’ on the ARI, missing on the later one altogether) as are the absence of engraved dots indicating half-stop clicks. Nice unblemished ‘Minolta green’ on the ft. engravings!

Same again at infinity, same difference in length (3mm)

Now the other side and here the white ‘Lens made in Japan’ on the ARII  and the simple ‘Japan’ in black on the early lens.

The big change for the ARII was not only the rear actuation of the aperture but in the iris itself, which had to be lighter and better balanced to react quickly to shut down and reopen adequately for the new shutter action on the now modernised cameras. Take a look down the barrel and the differences are obvious in the different shape of the iris itself. Still 8 blades, but very differently arranged, ‘back to front’, so to speak.

At f8 both look pretty much the same, though the earlier one is just a tad ’rounder’, but not enough to make any difference to the bokeh.

One surprise yet, is that the earlier, shorter by 3mm and narrower by 2mm in diameter lens, is heavier (402g against 382g) than the later one! Remember the difference in the thickness of the focussing-ring-casting?

The extra overall diameter of the later lens does have one potentially slightly annoying drawback… The DK57KD lenshood designed for it no longer fits on the lens backwards as it did on the early lens, so extra storage has to be found for it. Not really anything in the least important, but nonetheless worth mentioning.

Next up? Not sure yet, as I go into hospital on Tuesday to operate on my right shoulder again 🙁 I also have to make sure that the car is back on its wheels by then…