Lenses like this would have been hand made by artisans rather than mass produced by machines. The modern methods offer better quality control and economies of scale (the Ross probably cost its original owner 6 months salary!). The Victorians were actually pretty good at making complex machinery, just not at a price we would be able to afford today unfortunately...

Whippersnappers!

Seriously though, if you want to play with a wide variety of semi-ancient glass then get yourself a set of M42 bellows (the genuine Pentax ones I use are about as nice as they get) and a few cheap adapters. I have a M42>L39 step down ring and a further L39>25mm step down ring that between them will let me mount and focus almost any old lens. All you need then is some obscure 100 year old glass and you're away!

My Auto 110 kit has seen *no* use in over a decade but considering the pitiful prices they fetch on eBay I don't imagine selling it any time soon (or ever!). Makes an interesting talking piece if nothing else...

I bought a (used) lens at Ffordes last year which arrived broken and they refunded me quickly after I returned it and without fuss. Can't ask for more than that really.

135/2.5 = 54mm

So assuming there has to be a certain amount of space around that for the blades to fold back into then I'd imagine the barrel would have to be around 65mm minimum at the aperture point. I wouldn't say that a 58mm front element ruled out a f/2.5 aperture - on this particular lens the body is wider than the front so f/2.5 is plausible but space must be tight in there!

The K-m and the K200D used the Sony 10.2MP CCD sensor which is no longer in production. An unfortunate state of affairs but not one Pentax can be entirely blamed for!

After three days, two polite emails and one not-so-polite email to eBay's Customer Services (ha!) the Ennalyt still isn't showing up in searches so I've pulled it completely. Never had to pull an auction before in 8 years of trading on there and it's fair to say I'm steaming about it...

I've got more M42 gear to list next week so I'll add it to that lot instead - lovely lens and worth the wait honest!

I'm glad you enjoyed it and hope it's inspired you to go and buy some old glass yourself

That makes sense - I never did any darkroom work and I'd assumed the chemicals were measured by volume rather than weight. Now I know!

'scuse my ignorance but what makes them "photographic" scales as opposed to just scales?

I use P size filters with the DA12-24 and they're fine down to 15mm with only a tiny amount of vignetting between 12-14mm (I use the wide angle holder which only has the single slot). I don't have a DA16-45 to try but I see no reason why they shouldn't be OK...