Frit-Happens !

Technical Forum => Photo help => Topic started by: Sarah9959 on October 07, 2011, 07:33:40 AM

Title: Do I 'need' diopters?
Post by: Sarah9959 on October 07, 2011, 07:33:40 AM

Want to take good photos so don't have to piddle around with photoshop after.

Have set white balance and got greycard to set exposure - after reading Dickies Fritipaedia article.

However, even when I use macro the beads are too small in the frame and need cropping, I would like to avoid this if possible and wondered if I need to get a diopter to magnify the beads before the image is even captured on the camera's sensor? (I do NOT want to get macro lens, as think this would be overkill for my needs, as well as being horrifically expensive)!

BTW I have a Pentax K-x dslr

Advice greatly appreciated


Title: Re: Do I 'need' diopters?
Post by: Helen G on October 07, 2011, 07:42:12 AM
I'm not overly technical when it comes to photography (I only use the automatic option on my dslr) but having bought a macro lens recently (a sigma which I love) I did look at lots of other options, one of which was a set of macro filters to screw onto the end of your existing lens?

Title: Re: Do I 'need' diopters?
Post by: Sarah9959 on October 07, 2011, 08:06:41 AM
Hi Helen, yes I think it is the macro-filters I am asking about!!!! I'm not technical either, just saw them called that in an article I read!

When you say you love your Sigma lens, is that because it makes a lot of difference to your bead photos, or do you use it for other photographic stuff? Also, can I be rude and ask how much it cost you?

I do want to produce good shots, but am not sure if I can justify the cost of a proper macro lens for the limited use it will get.

Thanks  Sarah :)

Title: Re: Do I 'need' diopters?
Post by: ScarletLeonard on October 07, 2011, 08:38:47 AM
tbh cropping is nothing and to give you the right composition and balance probably a lot easier than piddling with a macro lens or filter.

You would need to resize the photos and save them for web anyway so photoshop is going to have to come into it. I set the cropping tool to the size I want the image to be for web (800x800px for me) then when I crop my square it is automatically resized to the size I need save for web, give it a name and its done. 

Title: Re: Do I 'need' diopters?
Post by: tomcat on October 07, 2011, 09:02:22 AM
agree about the cropping - the kx has a 12.4 megapixel picture size so cropping wont harm the picture quality much at all - what size lens are you using? I have a Kr and the zoom lense i have 50-200 is fine for web size quality pictures at the 200 end at its closes focus and then cropped.

Long boring technical bits -
It also depends on the iso you use - thats the film speed the lower the better the quality -
also the shutter speed - the higher the speed the better the image as there is less chance of shake or blur -
use a tripod and use an iso of 200 with a shutter speed as fast as the lens - so a 150mm lense - shutter speed at least 150th
on a tripod that will give you a good sharp picture then when you crop you can enlarge it a bit.

Sorry but no easy answer - I believe (may be wrong here - long time since i did much of this) that dioptre or close up lenses narrow the depth of field - thats the distance between the front part of the image that is in focus and the back of it - the shorter that is the less of the bead is in focus - the more you magnify with those lenses the narrower that gets and the more important the focus becomes to be sharp at the right place.

Golden rules
Use a tripod
Use additional lighting if you can (white balance to get true colours)
Use as slow a iso speed as you can for the light
get as fast a shutter speed as the lense size as a minimum
Get as large an f stop as you can this increases the depth of field so more is in focus and if your focusing is a bit out you stand a better chance of it still being in focus as the depth of field covers a wider area of the picture front to back

for instance ISO 200, Shutter speed 1/200th with f8 should produce a good picture that can be cropped by over 50% and still give a sharp image to put on the web

in essence its a balnce of all those things to get the best picture

Title: Re: Do I 'need' diopters? UPDATE
Post by: Sarah9959 on October 22, 2011, 04:52:07 AM
Hi, thanks for responses

I ended up buying a small macro type lense called a Raynox 150 DCR  - it cost approx 41 and is absolutely fabulous, has made a big difference to the photos as I can now get so much closer and therefore have much more detail.  Found out about it on an american photo forum I came across.

They are available via Amazon (isn't almost everything)!  This is the link in case anyone else is interested.

Title: Re: Do I 'need' diopters?
Post by: Pegasus on October 22, 2011, 09:43:35 AM