Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

stargazine_ep9_banner.thumb.jpg.05c1bdd298547fd225896a3d99c9bc17.jpg

Recommended Posts

Hi All, 

I wonder if someone can please help, I'm fairly new to astrophotography and confused about aperture. Basically I'm looking at a Canon EF-S 55-250mm lens. It has the specs
f4-f5.6 does this mean that the lowest point of aperture possible is F5.6 or will it go lower. What I find confusing is that I have a lens that's the EF-S 18-55mm lens which has the specs of f/3.5/5.6 however My camera does allow me to set the aperture at f/8 The reason I ask cause it is advised to use a low aperture of f/8 to capture images of the moon.

Any help and guidance would be greatly appreciated!

Share this post


Link to post
Share on other sites

It's a reference to the widest aperture available over the range of the zoom, typically more at the lower end of the zoom range, so in your example at 55mm it would be f4 and at 250mm it would be f5.6. 

All the smaller apertures are available at all zoom lengths, so f8 is available across the range of the zoom.

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By Abhinav
      which webcam is best for planetary imaging under 25 USD . If you have experience of any webcam for planetary work please help me out 
       
    • By Splodger
      Does Focal Ratio affect brightness or is it all about field of view. Will an f/5 scope show the Andromeda galaxy more brightly in the eyepiece than an f/12 scope, or is it just about fitting Andromeda in there and seeing more of the sky? Also does the Focal Ratio of a scope have any effect on the amount or length of exposures taken in astrophotography? Thanks. 
    • By MrGuGuZai
      Hi, my current telescope is Celestron ExploraScope 70AZ, thinking upgrade to skywatcher heritage 130P(came with 25mm ajd 10mm EP) ,  if i do, can i use the eyepiece (4mm) and x3 barlow from my old celestron on the 130P?
      One more question, i ordered a eyepiece camera Svbony SV105, i wonder what is magnification of this camera and how it work to change magnification. 
       
    • By astrosathya
      Just thought i'll bring this up as a point of discussion. Today, cooled CMOS Astro Cameras are available in plenty. QHY, ZWO and other variants of the same camera are selling for very reasonable prices. However, there was a point of time when astrophotographers used to cool down their DSLR's as a cheap OSC alternative to CCD cameras. Give a choice, I would've purchased a dedicated CMOS OSC which can cool to 40 C below ambient, but since I had a Canon 500D which I had self modded, I requested a friend Kaustav Chatterjee (an avid model railroader) to cold mod my 500D (he had cold modded his 1000D long back). This newly modded camera has a TEC12703 single peltier and cools to approximately 20 below ambient.What do you guys think?




    • By Nikolas74
      Recently i bought this brand new camera from David Hardie when he was doing a big sell out of some really nice items in excellent offers !!!
      Unfortunately the camera although brand new doesn't serve my purposes so I decided to sell it at exactly the same price which I bought it from David , it was a really special offer 🤪
      The camera new costs £1685 and I will sell it for £750 to be fair....🤪🤪🤪🤪
      Camera comes with all its extras and case in absolutely brand new condition....!!!!
      Info from FLO site :
      https://www.firstlightoptics.com/starlight-xpress-cameras/starlight-xpress-trius-pro-674c-colour-ccd-camera.html
      Postage expenses are on me, secured package.
      Paypal accepted ,just buyer pays the fees.
      If payment is in EURO we will just calculate the daily exchange rate at Xe.com.
      Many thanks !
      Nikolas.
       
       



×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.