The first of the F1.7 pictures is at f2.8 so that's the comparison.

Yes, I systematically stopped down with each lens. Results at f8 are below.

Perhaps worth noting that I tried to focus (manually) on the 'snake's tongue' fork and there might have been very slight subject movement (air is rarely completely still). My main interested was the out of focus areas in real world photography, sharpness would have been easier and more accurately compared using a flat, indoor target.

Sigma 105mm, f8



F50mm + tube, f8



Steve

I bet they don't make 'em like they used to!

Steve

Here are three shots of an acanthus flower (part of the 'every type of flower in the garden' project). First is with the Sigma 105mm macro (film era) wide open (f2., second and third are Pentax F50mm f1.7 plus 20mm tube at f2.8 and wide open (f1.7) respectively. All are about 0.5 magnification and same viewpoint but necessarily different working distances and thus perspective for the Sigma and Pentax.

There are subtle differences between the two at f2.8 but which do you prefer and why? And does having f1.7 available with tubes add something useful?

1. Sigma 105mm, f2.8



2. F50mm + tube, f2.8



3. F50mm + tube, f1.7



Steve

Derek, I believe you're the first person who has ever said anything flattering about my use of the English language. My old English teacher would be surprised, my wife would probably laugh (so I'm not going to tell her) and I'm feeling all shy and embarrassed.

Steve

There is talk in another forum about the 16-85 being prone to screws becoming loose. £200-300 sounds a bit steep for a loose screw, but if it has come adrift and caused other damage then a lot might need replacing. If the problem was just with, say, early production or a particular batch, there might be a fix that would now be used in a repair so the repaired lens would be good for a long time. Do the repairers offer to diagnose at a modest fee and quote for full repair then you decide whether to go ahead? Good luck, whatever you decide to do.

This is making me nervous. My 16-85 hasn't been used it for a while, will it still work...?

Steve

You could always buy a Q-K mount adapter, then all your K mount lenses become oddball lenses on the Q.

But a pocketable 80-240mm f2.8 zoom (OK, OK, equivalent FL) is definitely a good thing to get next. Then comes the 01 ...

Slightly off-topic, but might be useful, it's worth noting that buying a used Q lens isn't quite the same as a used K-mount lens. The Q doesn't have a mechanical shutter so nothing to wear out. However, there is a leaf shutter in the 06 and other non-toy lenses so that's where shutter lifetime will hit. I've never heard of how many activations it should be good for, or even whether there's a way to check shutter count, but might be worth asking about usage (and hoping for an honest answer).

Steve

You didn't mention the 01 standard prime. It's a good lens and f1.9 can be very useful at lower light levels, (particularly with the original Q which appreciates getting a decent number of photons on the sensor). I've got an 01 (as well as the 02 and 06 zooms) and wouldn't swap it for any number of toy lenses.

I didn't bother with the 04 and 05 toy lenses. As far as I could make out, they are for lo-fi photography. If you're into that sort of thing, they'll be what you need. But if not, it's as you say - they seem, err, well, a bit pointless. On the other hand, if you have the 02 and 06 zooms then the 03 fisheye would be worth considering if you think fisheye might be fun (which I did, so got one and do use it occasionally).

Enjoy your Q. It's a camera for having fun.

Steve

Ain't nature wonderful! I suppose we mustn't complain, it's probably doing less harm to us than our plastic is doing to them. Does the 5th one suggest why hoodies were invented?

An interesting set of pictures illustrating an interesting fact that hadn't previously reached this southerner. Thanks for posting.

Steve

Thanks Algi, you might be onto something.

Being out of gamut hadn't crossed my mind. I use sRGB for everything, mainly because it's supported (even if not perfectly) by every screen in the house. The K3 is set to use sRGB colour space. Now, out of gamut colours must be recorded as something, but what? If they are recorded as the nearest sRGB colour, or even spread across a narrow range of sRGB, that would certainly result in loss of detail. Some experimenting with K3 set to AdobeRGB seems to be on the horizon - but what experiments when you don't have an AdobeRGB screen? Life is full of questions...

That dpreview thread is interesting. "Decreasing brightness increases saturation of all colours except yellow which gets more saturated as brightness increases." ties in with my experience. Then the perfect punchline: "There is a scientific explanation of this phenomenon, but I can't remember it".

Thanks again.

Steve

Nothing wrong with these! Love the flies going about their business. And the last one has a superb abstract, 3-D quality about it that is almost sculptural.

Steve