petrochemist

Lives in United Kingdom United Kingdom
Joined on Feb 26, 2014

petrochemist's recent activity

  • There are several types of Industar lenses around 50mm. All are quite small but the collapsible Industar-22 must be the smallest (80g). (Two other collapsible models exist which are slightly ...
  • Were perhaps , but I'd expect mirrorless users to now exceed them by a huge margin. Canon APSC models may also be bigger users than the FF club - there are certainly a larger number of them around. ...
  • Iso-propanol (also known as propan-2-ol, or 2-propanol) is generally considered to be highly suitable. You'll want a high purity grade to prevent muck being left on the lens afterwards). It sounds ...
  • Thats right, as determined by the laws of optical physics. Additional optics such as relay lenses would be needed to make it work without shortening the optical path. AFAIK thats NOT what they are. ...
  • Those I saw with a quick google are designed to fit in the eyepiece tube & provide a c-mount connection on the other end. Given the number of them available from astronomy sources I would be ...
  • The standard 37mm filter thread is M37x0.75, it's possible some enlarger lenses where made with a 0.5 pitch as for some reason they seem to avoid using standard photographic threads. M37.5 & m30 ...
  • Some of the shots my dad had taken in film days were printed to at least 8m x 3m (British 64 sheet billboard) Admittedly those were probably all medium format or even large format, though 35mm was ...
  • While there are those who like HDR, many others hate it, especially when done to such an extent. I personally would prefer this with the boats far more silhouetted.
  • I believe you are referring to the focusing ring - which is the control for manual focusing. Not all lenses have a focusing mechanism built in, but any that do will have a focusing range even if ...
  • The guy in the shop obviously doesn't know what he's talking about! Shorter lenses work just fine & give more magnification for any given extension...
  • The ideal one would have illustrations of each mount, complete with dimensions, and notes of easy identification clues... But that becomes a great deal more work, and can only be done for mounts ...
  • Approval follows from you making posts to the forum. These are then highlighted to moderators who will check them. After a few appropriate posts to the forums approval is usually fairly automatic. ...
  • There are 3 sub sets to M42 lenses: The earliest are preset usually with a double aperture ring one which doesn't move the aperture and the other that only closes down to the value set on the ...
  • IIRC the idea was popular enough, there was just concern about posters adding the tag themselves - surely everything I say is informative :-) I think the fixing of follow up posts could also be ...
  • I've expanded/updated one I found on line: Mount matrix
  • Replied in Mirror lenses
    The Tamron SP 500 is well regarded among camera mirror lenses but will need careful handling like any manual lens of this focal length. The celestron models you refer to are I think astronomical ...
  • I assume you mean lightning (thunder is only the related noise). This issue is probably heavily location dependent, here in the UK well over 90% of our rain comes without lightning. The metal in a ...
  • I've used my Pentax cameras with a weather resistant lens in heavy rain & spray without any extra cover. Though I've generally tucked it inside my coat between shooting opportunities. I use a fully ...
  • Large format with a scanner was exactly what I was going to suggest. If your project is about the optics side then you don't really need the digital part at all just viewing on the ground glass ...
  • Two mirrors will not invert the image you need an odd number of reflections to do that. A single mirror is used in my large format reflex viewer, mimicking the action of many medium format viewfinders.
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