====== List of thing to check before buy ======

Feature side
  * has a viewfinder ?
    * if viewfinder is electronic, the resolution ?
  * preview LCD resolution ? and size ?
  * Zoom range ?
  * Sensor size ?
  * weight ?
  * battery type ?
  * brand and looks ?

===== about preview LCD resolution and size =====

It seems nowadays, manufactures never put a resolution like 640x480 or follow display resolution guide like when you buy a monitor, because they are shy to tell, just like they never mention their sensor size in compact cameras.

Resolution I mean, how many dots they can display
  * 1280x720=921,600 dots (like Pentax Kr)
  * 800x600=480,000 dots
  * 320x240=230,000 dots (like my Pentax Kx)

Size I mean, like 3 inch screen or 2.7 inch screen,

===== Old Film Manual Lens on Modern Digital SLR =====

**Nikon Old Film lens and Nikon DSLR**

Please refer to this nice guide for old nikon lens compability with nikon cameras:
  * http://www.kenrockwell.com/nikon/compatibility-lens.htm

A General guide is Old (since 1977) **AI, AI-s, AF (current F mount)** lens can **mount directly** with **Manual Focus**.

While even old (before 1977) **pre-AI (non-AI, techinically ancient F mount)** will **Not** mount.

**Pentax Old Film lens and Pentax DSLR**

A nice history and reference chart here
  * http://www.bdimitrov.de/kmp/technology/summary/index.html

  * Old Pentax lens with M42 mount (before 1975) can mount with a **pure metal ring adapter** on Pentax DSLR.
  * Old Pentax lens with "K mount" (noted as "pk mount") (after 1975) including **K, M, A, F, FA, DA, DAL series** can **mount directly** with **manual focus**.

A General guide is **all Pentax lens can be used on Pentax cameras.**

**Canon Old Film lens and Canon DSLR**

  * Old FD mount Canon lens (since 1970) will only mount with **"Optical correction adapter"** on Canon EOS DSLR, **bad Optical correction adapter will affect the optical performance of the lens**
  * Old Nikon, Pentax, Olympus OM, Leica R, C/Y mount, M39 mount, T mount, Rollei (35mm) Mount lens just requires a **pure metal ring adapter** to Canon EOS DSLR with manual focus,
  * Old Minolta MC,MD, Voigtlander Retina DKL lens requires **"Optical correction adapter"** to Canon EOS DSLR with manual focus.

**Minolta Old Film lens and Sony DSLR**

  * Old Minolta **AF mount (noted as MA mount or Sony Alfa mount)** lens will mount **directly** on Sony A DSLR with Auto Focus.
  * Old Minolta SR mount lens **(MC, MD series)** will only mount with **"Optical correction adapter"** on Sony A DSLR with **manual focus**, **bad Optical correction adapter will affect the optical performance of the lens**
  * Old other lens with M42 mount can mount with a **pure metal ring adapter** on Sony A DSLR with **manual focus**.

**Sony E mount camera and Micro 4/3 camera**

  * as Sony E mount camera and Micro 4/3 camera have even shorter lens to film distance, (while Canon has shortest among above except these 2), almost all the old manual lens can be used with a **pure metal ring adapter** with manual focus on them.

**Range Finder Camera lens on Modern DSLR**
  * **[[http://photo.net/pentax-camera-forum/00OKJz?start=0|You cannot use rangefinder lenses on any SLRs other than as a very limited macro.]]**
  * While, you can use Range finder Lens like [[http://theonlinephotographer.typepad.com/the_online_photographer/2008/12/leica-lens-to-p.html|Leica lens]] on [[http://www.rugift.com/photocameras/leica-m-sony-nex-adapter.htm|Sony NEX e-mount cameras]] and [[http://www.rugift.com/photocameras/leica-m-panasonic-g1-adapter.htm|Micro 4/3 cameras]] with a **Pure Metal ring adapter** with No Limitation, as they requires even short lens-to-film-back distance.


**Notes:**
  * adapter with electronic focus confirmation will help you easily get notified when manual focusing is focused.
  * those optical adapters are also available without optical part, which will make the manual lens short-sighted, can focus closer but can't focus infinity.
  * All mounts are exchangeable with certain optical correction adapter, however, for best optical quality, only Lens with pure metal ring adapter are recommended.
  * Modern Auto-Focus digital lens often has no Aperture ring, thus not that exchangeable between brands; However, there are certain adapters with manual aperture control built-in, then it will has full manual function with digital lens.
  * Adapter reference: http://www.rugift.com/photocameras/adapter-rings.htm
  * Mount reference with images: http://rick_oleson.tripod.com/index-99.html