The Pentax Forum.co.uk

The UK based Pentax Photography Forums

Skip to content

Follow us on Facebook BUTTON
  • About TPF
  • • TPF Terms
  • • FAQ
  • • Icon Help
  • • Key Commands
Advanced search
  • Welcome to The Pentax Forum.co.uk! A new community for PENTAX Photographers. Non Pentax brands welcome!
    Click here to register and join in!
  • Forum index
  • Gallery
  • Search
  • Forum index ‹ Lenses ‹ Lenses
  • Change font size
  • Print view
  • Register
  • Login
  • View active topics

Pushed too far

Chat about lenses. We love them!
Post a reply
8 posts • Page 1 of 1

Top Forum Index Page New Posts

Posted on Tue Sep 18, 2018 12:56 pm

Pushed too far

      

Hi, whilst away on the Isle if Arran had the fortune to spot some birds of prey.
I have the K3II and had the 55-300 zoom fitted. The overall picture is poor in my opinion.
Overcast day with light rain. Aperture wide open and at full zoom. Had spot focus on which was fun aiming for a small fit in the viewfinder. ISO was at 3200 and 6400 to try and maintain a good shutter speed.
Got them on the computer to try and enlarge them and the subject is either grainy or out of focus. Maybe a higher ISO to increase shutter speed again but then the grain creeps in when increasing image on PC.
Just wondering if anyone has used the Pentax teleconverter rather than buy an oversize lens.
Was thinking of swapping to the sigma 18-270 and the 1.4x adapter which would cover just about every eventuality needed.
Spotted an eagle earlier and managed to shoot a few with the 18-50 lens but he flew off before I could swap lenses.
Any advice for future would be appreciated.


Sparkie67
Posts: 7
Joined: Sat Dec 30, 2017 7:31 pm

Top Forum Index Page New Posts

Posted on Tue Sep 18, 2018 11:23 pm

Pushed too far

      

Watcha :)

Have you adjusted the autofocus fien adjustment for that lens. First thing I'd check. :)

Regards Shutter speed and ISO, I'm all for upping the ISO to maintain a fast enoguh shutter speed. Grain can be reduced with decent Noise reduction, but camera shake/motion blur is nigh on impossible to reduce


Smeggypants
User avatar
Janitor
Posts: 5234
Images: 0
Joined: Sun Jul 06, 2014 4:56 pm

Top Forum Index Page New Posts

Posted on Wed Sep 19, 2018 6:01 am

Pushed too far

      

What mode were you on?

There's a setting for ISO auto behaviour, and I've set mine to fast. That instructs the camera to do just what you're after, in terms of targeting a faster shutter speed with high ISO, rather than trying to keep ISO low to keep noise down and with a slower shutter speed.

That, plus AF fine tuning is about all you can do, before having to opt for a much more expensive/longer reach/wider aperture lens.


richandfleur
User avatar
Posts: 1780
Images: 1
Joined: Fri Aug 08, 2014 12:36 am

Top Forum Index Page New Posts

Posted on Wed Sep 19, 2018 12:01 pm

Re: Pushed too far

      

Thanks for the replies, I was using manual mode with single spot focus.
With reference to fine auto focus, can someone explain more please. Is it an extra setting i’ve missed in the camera.
Maybe better in future to set shutter priority and let camera do the rest.
Still looking at the Sigma lens as an allone option for close and tele use if anyone has experience of it.
Thanks
Andy


Sparkie67
Posts: 7
Joined: Sat Dec 30, 2017 7:31 pm

Top Forum Index Page New Posts

Posted on Wed Sep 19, 2018 8:42 pm

Pushed too far

      

Rather depends if your soft images are due to motion blur (shutter speed too long to freeze motion) or missed focus.

Each lense autofocus settings can be calibrated to the camera, and often this can improve the focus accuracy.

Frankly all in one lenses are usually fairly average. It costs a lot to go really wide or really long and that’s just the way it is. I think the Pentax 55-300 is the best of the cheaper all in ones.


richandfleur
User avatar
Posts: 1780
Images: 1
Joined: Fri Aug 08, 2014 12:36 am

Top Forum Index Page New Posts

Posted on Thu Sep 20, 2018 2:23 am

Re: Pushed too far

      

Sparkie67 wrote:Thanks for the replies, I was using manual mode with single spot focus.
With reference to fine auto focus, can someone explain more please. Is it an extra setting i’ve missed in the camera.
Maybe better in future to set shutter priority and let camera do the rest.
Still looking at the Sigma lens as an allone option for close and tele use if anyone has experience of it.
Thanks
Andy




In the K-5 it's in the custom menu [#26. AF Fine Adjustment]. I don't have a K-3 but I suspect it's somewhere similar. Basically you take a series of test shots wide open for narrowest DOF on a subject that allows you too see if the lens is front of back focussing and adjust until your target is in focus. This can change with subject distance so best to check with a focal distance that you mainly use the lens for.

I've had some lenses that seriously back or front focus which I've had to correct with this parameter.


Smeggypants
User avatar
Janitor
Posts: 5234
Images: 0
Joined: Sun Jul 06, 2014 4:56 pm

Top Forum Index Page New Posts

Posted on Thu Sep 20, 2018 7:05 am

Pushed too far

      

Having never shot distant wildlife I cannot help in that respect. However, there are some general points arising from your first post:

"I have the K3II and had the 55-300 zoom fitted.....Overcast day with light rain."
If you were you shooting in the rain, do you have the WR version of the 55-300? I doubt that the Sigma 18-270 will be weather-resistant. Also, if it was raining and your subject was far away, there will have been a huge number of obstructions (i.e. raindrops) affecting image quality.

"Aperture wide open and at full zoom."
Lenses are usually nowhere near their best at their extremes.

"ISO was at 3200 and 6400 to try and maintain a good shutter speed."
Obviously there will be more grain (noise) at higher ISO values and noise reduction will reduce detail in the image.

"Got them on the computer to try and enlarge them and the subject is either grainy or out of focus."
Do you mean cropping the image to increase the size of the subject within the frame? If so, you will also be accentuating any graininess or softness introduced when the image was shot.

"Was thinking of swapping to the sigma 18-270 and the 1.4x adapter which would cover just about every eventuality needed."
Adding the converter will not help image quality, as there are several extra glass surfaces that will degrade the image. Also it will cause a reduction of light by one stop, so you will either have to further increase ISO or reduce shutter speed, potentially exacerbating the problem.

Philip


MrB
Posts: 423
Joined: Mon Jul 14, 2014 11:13 am

Top Forum Index Page New Posts

Posted on Fri Sep 21, 2018 2:58 pm

Re: Pushed too far

      

Thanks again for the replies.
Will look for the fine AF adjustment.
Sounds like I need to either get nearer the subject, wasn’t easy at all. Maybe invest in a bigger lens in the near future.
I know it’s never easy when an opportunity arrives, and you just have to go with what you have got. And maybe more practise at getting the correct settings.
The Pentax is the WR version, and see your point about the Sigma maybe not having weather protection.

Many thanks
Andy


Sparkie67
Posts: 7
Joined: Sat Dec 30, 2017 7:31 pm


Post a reply
8 posts • Page 1 of 1

QUICK REPLY

:) :D :yippee: :thumb: :rofl: :cheers: :cool1: :wink: ;wave: :nono: :confused: :eek: :( :oops: :fingers_crossed: :doh:
Help on how to post Images - View More Smilies
 
Share this Topic on Facebook:
Img
  • View active topics

Return to Lenses

Who is online

Users browsing this forum: No registered users and 1 guest

  • Forum index ‹ Lenses ‹ Lenses
  • The team • About TPF • Terms and Conditions • Cookie Policy • Delete all board cookies • All times are UTC • Top of Page
Powered by phpBB3 © 2007 - 2014 phpBB Group - Additional Coding by Bug Bug & Bug™ ©2014

Smeggy ©2014
cron