Archive

Archive for the ‘photography’ Category

Tack Sharp Portraits

April 15, 2014 Leave a comment

Until few months back, I used to wonder: why is it that my portraits aren’t tack sharp? I would feel that I could have eeked out more sharpness. However I wasn’t sure what was it that I was doing wrong. I would make sure that I:

  • Use spot focusing and choose a focus point so that I could aim for the eyes,
  • Choose a shutter speed that is fast enough to freeze motion when I want it to,
  • Choose an aperture so that I could blur the background,
  • Choose the lowest possible ISO,
  • Try to adjust my exposure settings to expose for highlights and
  • Choose a focal length greater than 50mm.

However, irrespective of the output, I would always feel that the portrait could have been sharper. I had seen stunning portraits (with the same lens) and I knew it could be done. Yes, the glass matters, but my Tamron 17-50mm f/2.8 wasn’t too shabby.

After much research, I found that not all apertures of the lens capture images with the same sharpness. (What? How can this be true? This called for a serious investigation.)

I googled for a lens-test chart. To test the lens, I stuck the chart to a wall. After arranging sufficient ambient lighting, I setup the camera on a tripod and switched to aperture priority mode. After setting the ISO at 100, manually focusing on the chart with live view and using a release cable to trigger the camera, I took photographs for all aperture settings at different focal lengths.

The results were astonishing. See the pictures below at 17mm. With all other parameters fixed (except for shutter speeds, which is understandable) the photograph at f/2.8 is not as sharp as the one at f/4.0. Similarly, the one at f/4.0 is not as sharp as the one at f/5.6. However I started to lose sharpness at the other extreme too. I observed the same behavior at all focal lengths, though with slight variations. Nevertheless, the trend was the same. Sharpness was poor at extreme apertures, which in my case was f/2.8 and f/32.

f/2.8, 1/400 sec, 17mm, ISO100 f/4.0, 1/200 sec, 17mm, ISO100
f/5.6, 1/60 sec, 17mm, ISO100 f/22, 1/4 sec, 17mm, ISO100

The lesson was that by stopping down once (f/4.0) I would get a pretty good image. Stopping down twice (f/5.6) would result in a much more sharp photograph. From there on I would observe diminishing returns, until the sharpness started to deteriorate.

Therefore, your f/1.4 may not produce pictures as sharp as you would have expected it to produce at f/1.4. While it is important to consider other aspects — e.g., avoid camera shake, making sure that you’ve focused where you intended to and choosing other exposure settings — avoiding extreme apertures is important to obtain tack-sharp photographs.

I have not tested the same with L series lenses. I would expect similar trends though.

There is another aspect to this discussion; I also realized that we should not confuse the lack of sharpness due to extreme aperture settings with the blurry feel of photographs that have a narrow depth of field. When we choose a small aperture (say f/16), we are increasing the depth of field; when we choose a wider aperture (say f/2.8), we are narrowing the depth of field. Depending on your focal plane, a photograph with a large depth of field may have a “feel” of being sharper than a one with a narrow depth of field. However, the discussion above is not with reference to the overall feel of the photograph, but instead about the sharpness of the subject(s) that fall within the region that is in focus.

Categories: photography

Hokie Snow

March 12, 2012 2 comments

(2/19/2012) Finally! It snowed; it snowed as it typically does in Blacksburg. I wasn’t feeling well, stressed with all the juggling that I have to do, so I thought, I am going out for an adventure. This will be a nice distraction. Crazy as I am, I charged my camera’s batteries, setup lens protection — snow melts into water you know and that can get inside the camera (smart thinking :P), — put on layers and layers of clothing, cued the music and off I went.

As soon as I stepped away from the building, whoooaaa!! it was pretty slippery out there. If this was a sign of things to come, I’d be sitting on the ground more than taking pictures. Anyway, I took it as character building and moved on.

While I was walking down the winding toms creek road, a few police cars went by. Someone must have got into an accident. It was snowing pretty heavily. I had to spit out snow every few steps. Never the less, the views were spectacular.

By the time I reached campus, it must have snowed a couple of inches. Snow in my face, on my shoulders, on the bag. The camera was all covered in snow. But then, I was out for an adventure.

I was glad that I made the effort. It was worth it. The view from War Memorial was amazing. Everything was covered in white. There were so many people around, some making snowmen, some building thrones to sit on, some just mucking around throwing snowballs. I had to wait minutes to get a reasonable shot. Nevertheless, all the wait was worth it in the end.

The trees looked beautiful. They had this majestic appeal to them. I do not think the pictures do justice to the beauty.

And then someone opened the flood gates. It started snowing like crazy and everyone wanted to get out of there. I thought that I too should start heading back, I decided to take the long route and go via duck pond and see if I can get some more shots there.

The snow would just keep coming and coming.

But the I thought, wait a minute, the poor photographer is always left out. I need to get some photographs of myself. Despite the god-awful snow in my mouth and finding its way onto my back through my shoulders, I setup the tripod and took few pictures of myself. Got all my jeans wet.

Anyway, as I was trotting back along the duck pond, trying to exercise my creative abilities, this girl comes up to me, “ooh, so you are on a photography assignment? … by the way, do you know when does the bus come?” and I was like … “hahahaha … No. I just enjoy photography … unfortunately I do not know the schedule. Sit tight and bus should be here”. She must be new and I realize how lost new students feel; I was once a new student. I imagine that the delay was because there was an accident. The driver slammed the SUV into the fire hydrant :|. It doesn’t seem much, but trust me, there was a lot of snow. Driving would not have been easy. In fact, it is snowing at this moment.

I am just glad that I got new tires for my car in time.

Anyway, at this time, my fingers stared aching. I removed my gloves, and what do I see? Blue fingers. OK, I realized, time to head home before I lose my fingers. I couldn’t pack the camera. If I tried to do that, it would have got the lens all covered with snow. I was barely keeping snow out of my mouth.

My fingers hurt so bad, that I thought of calling someone to take me back home. But then I went towards a building. Brushed off all the snow, all that I could and stuffed the camera in the bag and started rubbing my hands fiercely. In few minutes, I started feeling better. Thanked Allah that I got my fingers back. Time to head home.

On my way back, I was thinking I should have taken pictures of my blue fingers — a souvenir of my escapade. Anyway, getting back home was not easy either. Toms creek is not a steep climb, but with all the snow, it was difficult to walk back. And then my toes started hurting. Note to self: no snickers in snow.

Anyway, I kept chugging away. Along the way, one or two people passed by me. Smiling as they usually do in Blacksburg. But there was something about their smile. I couldn’t figure it out untill I got back home. My red cap had turned white, I had a white beard and a grey and moist mustache, snow on my shoulders …. No wonder they were smiling. It seemed as if I had surmounted K2 or something :).

I got back home and changed. After few minutes when blood started flowing to the numb parts of my body (e.g., butt cheeks) I realized what all had frozen.

Nevertheless it was fun. It has been quite some time that I got to enjoy photography. I missed an opportunity in Fall last year. I hope I’ll be able to mange it this year.

The views are amazing. I wish I could teleport everyone so that you could experience the same. See the al

Now I am feeling hungry, it is time to cook dinner. I think I will make biryani and some pakoras perhaps; the occasion demands so.

Categories: photography