Flaws @ f/45

During my Houmei photoshoot I stopped down my Sigma EX 105 mm f/2.8 DG Macro lens to f/45 for a shot in an attempt to capture more focus into the frame. This often turns out to be more of a pain than I think it will be as it reveals every piece of dust that has affixed itself to my sensor. And in addition to each piece of dust, revealed also are the streak marks from the many attempts to clean the sensor.

Now, I’m quite used to using the spot removal tool in Adobe Lightroom to remove dust specks from my photos, and in most shots I’m in between f/2.8 and f/16 and generally only see around 5 dots maximum. However when stopping down to f/45 like in the header image (for fullsize, right-click it and open the link in a new tab), you can see there are considerably more. There are in fact 176 specks of dust that I removed from that image, and sadly found six more just now as I was counting them raising the total to 182. That’s obscene and tells me that I desperately need a new camera with one of those fancy self-cleaning sensors. It’s impossible to keep my sensor clean enough to use apertures as small as f/45 while taking the camera out on trips and swapping lenses outdoors.

And just to give an example of a streak mark left over here’s a close up of the same image, you can see two lines crossing Houmei’s face. I’m not entirely sure they’re streak marks from cleaning but it’s the best explanation I’ve come up with so far. I half think I’ve complained about these in the past as flaws on figures when in fact they’re a flaw in my equipment.  Rather disappointing.

Comments

  1. Ex14 says:

    Erm….I hope u do know that stopping down THAT much actually MIGHT cause ur pictures to be more fuzzy ^^;;

    • Aka says:

      Yes and no. Stopping down that far allows more of the picture to be in focus, however it means the picture wont be as sharp.

      • Ex14 says:

        OO ok, kinda get it ^^; I think i misunderstood what u meant cause most ppl when they mean in focus = sharpness usually ^^;

        • Aka says:

          Well to be more specific I suppose…. Dropping down to f/45 would significantly increase the depth of field, allowing more of the subject to appear to be in focus. The benefits of the added DOF outweighed the cons of the softened detail and focus.

          A similar type of shot with a larger aperture. You can see less is in focus, though what is in focus is sharper. You can also see I missed some specs on Houmei’s face, uguu~

  2. f/45? You, sir, are crazy! I guess you reallllly wanted it all in focus? You’re going to probably get lower quality images at such a narrow aperture, you know 😉

    Although I sympathize with you on the dirty sensor. I do have one of those fancy self-cleaning sensors but after 2 years of use, my camera has collected a bit of gunk. I’ve tried cleaning it myself but it hasn’t helped much. I guess I’ll be sending my camera off to Canon to get cleaned ^^;

    • Aka says:

      I’d have gone higher if I could. I understand the benefits and draw backs of higher f-stops as mentioned with Ex14 above. More in focus, but a softer edge to everything. But when you’re taking a 6 MP photo and reducing it to 1.7 MP or less for the web, this isn’t really always an issue.

      Ah, so even the self-cleaning sensor isn’t infallible. Damn!