= Buff Einstein 640 =

<<TableOfContents>>

Product homepage: http://paulcbuff.com/e640.php

Rob Galbraith has a [[http://www.robgalbraith.com/bins/multi_page.asp?cid=7-10053-10715| more serious review for sports usage]]. This page is mostly just me rambling.

== Why? ==

 * High output
 * Portable
 * Smart wireless control system


== Specs ==

 * '''640 Ws''' (wattseconds) output
  * Comparison to hotshoe strobe guide numbers is basically impossible, '''the internet suggests ~160 Ws for top-end speedlights'''
 * Weighs just on '''2kg'''
 * About the '''size of a tissue box'''


== Why an Einstein vs. an Alienbee? ==

Compared to the [[http://paulcbuff.com/b1600.php| B1600]], which is also rated at 640 Ws:

 * Universal voltage
 * Cheaper wireless receiver modules
 * Wireless controller is more expensive, but far more capable
 * Heavily integrated 2nd-gen remote control, the Alienbee 1st-gen cybersync stuff is kinda janky (perfectly functional, just not ''as'' nice)
 * Better output-level control, another 3 stops of latitude
 * Only ~350g heavier
 * Brighter modelling lamp (250W vs. 150W)
 * Modelling lamp can track flash output ''with offset''
 * Slightly faster cycle time
 * Flash duration proportional to power, like hotshoe strobes

== Comparison to a speedlight system ==

||<rowbgcolor=lightblue> Attribute || Einstein 640 || Speedlight SB-800 || Notes ||
|| Weight              || 2kg || 500g || They're probably fairly close in terms of output-per-gram ||
|| Portability         || Much larger || Compact even with attached foot || - ||
|| Light output        || Absurdly high || Rather high || Numerical comparison would require some apples-to-apples testing ||
|| Burst capability    || Good || A few flashes, depending on power || Not specced. Try opto-slaving the E640 to a speedlight's modelling light for a laugh ||
|| Cycle time          || 1.7sec to full output || 2.7sec to full output || 2.3sec quoted for newer speedlights ||
|| Output control      || 1/10th f-stop || 1/3rd f-stop || - ||
|| Continuous shooting || Basically non-stop || Subject to overheating || Speedlight behaviour varies between models. Buff gear only defines a maximum continuous usage for the Zeus lineup ||
|| Modelling lamp      || 250W bulb || None || Usefulness heavily dependent on your style, E640 cannot use lamp with battery ||


== Annoyances ==

 * Wireless receiver sticks out a long way, can't be stowed with it installed
  * The Buff carry bag doesn't solve this, but has a little pouch in the lid for keeping the receiver


== Portability ==
Fastpack 200