Monday, June 25, 2012

Hosta Buds and Blooms

Something I'm learning about photography... how to create bokeh (light bubbles in the background).   I want to get more adept at capturing it.  I've had some success with it lately, but only because I know two things : 1) focus on an object in the foreground, and 2) the more distant and lit the background objects are, the better my bokeh will be.  I just focus on my subject and make sure I'm properly metered for light.

What I want to get better at understanding (or manipulating) is how ISO, shutter speed and aperature work together.

Here are a few photographs I took of the hosta blooms on Sunday.  I'm going to give their stats below each one and see how they compare.




Camera  Canon EOS Digitial Rebel XT
Exposure  1/160
Aperture f/5.6
Focal Length  67 mm
ISO Speed  200





Camera Canon EOS Digitial Rebel XT
Exposure 1/100
Aperture f/5.6
Focal Length  80 mm
ISO Speed 200





Camera Canon EOS Digitial Rebel XT
Exposure 1/160
Aperture f/5.6
Focal Length  80 mm
ISO Speed 200





Camera Canon EOS Digitial Rebel XT
Exposure 1/125
Aperture f/5.6
Focal Length  80 mm
ISO Speed 200

(BTW, Notice the bug heading for the open bloom. Doesn't it look like it's leaving a jet stream? I think it's really a spider silk... but nice placement!)





Camera Canon EOS Digitial Rebel XT
Exposure 1/250
Aperture f/5.6
Focal Length  80 mm
ISO Speed  400





Camera Canon EOS Digitial Rebel XT
Exposure 1/60
Aperture f/5.6
Focal Length  80 mm
ISO Speed 200





And just because I like them, here are a couple of the hen and chicks blooms with a little peony bokeh {love}.



Camera Canon EOS Digitial Rebel XT
Exposure 1/60
Aperture f/5.6
Focal Length  80 mm
ISO Speed  400





Camera Canon EOS Digitial Rebel XT
Exposure 1/80
Aperture f/5.6
Focal Length  80 mm
ISO Speed  400




What I don't understand, but aim to find out, is why my f-stop is never below a 5.6. 

Photogs, feel free to chime in!  ...Kristiina?

- - - - - - - - -

Oy!  It's my lens. 

I vaguely remember Kristiina mentioning something about this.  -_-

From the web...  "...This is normal, and I'm guessing you have a standard type kit lens.

If you look at standard kit lenses (and similar lenses) there will be two f-stop numbers. Usually it will be something like f/3.5 and then a f/5.6

The first number is the max aperture when you are at the wide setting, and 5.6 is the max when you are zoomed to the max. This is normal and a physical limitation of the lens..."


Ohhh.  Yeah... 






3 comments:

Mom said...

Beautiful photos, Pammie....However, you are way over my head! I just point and shoot!! Ha

Kristiina said...

Your googling was right. When you're fully zoomed, the larger of the 2 numbers is as low as it can go.

You're getting really good with your 'light bubbles'. That cracks me up. As for iso, the higher the number, the more light you have to play with. Always keep it as low as possible to keep your grain/noise in check.

The shots with the peony are beautiful and I like your composition but think you have pushed your limitations with shutter speed to its absolute max. I haven't been able to look at them big but have to wonder if they could have been more crisp if you had raised your iso AND your shutter speed.

I know we've talked briefly about focal length to shutter speed ratio before but it's worth repeating. With a full frame sensor your speed shouldn't drop lower than your focal length. Example, if I'm shooting telephoto at 300mm, my shutter shouldn't be lower than 1/300. This is to avoid camera shake blurriness. Because you have a crop sensor it's like shooting with a longer focal length. A 50mm responds like a 80mm and a 200mm responds like a 320mm. Think of it as an in camera digital crop/zoom that you can't undo. Because the sensor size tricks our cameras eye, we need to account for that with the shutter speed. Always multiply your focal length by 1.6 to find your minimum shutter speed. I question the clarity of the peony shots only because your speed was 1/60 with a focal length of 80mm. It should have been no lower than 1/125-1/150. Of course you could have used a tripod if a slower shutter isn't avoidable but you still have to take into account the subject moving too. Wind.

I hope you have enjoyed this lesson. :-) Xoxoxoxoxo

Ziegler Peeps said...

I enjoyed this lesson!
Thanks Pam and Kristiina!
Can't wait to experiment...wish I could spend a day in training with u 2!