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07-24-2013, 06:06 AM   #1
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Bad DAL 55-300 lens?

Early June I purchased a 55-300mm. I'm new to DSLR and not a "photographer" in any sense of the word, just a hobbyist. I was uncomfortable with the quality of the lens from the start, but until this morning never had convincing evidence. The moon is near full and I love moon shots, so I decided to try the new lens. Long story short, I could not get one snap in focus. Moon features were easily visible to the eye, but I could capture nothing. I have some nice shots with my K-01 using a Nikon lens (with adapter) so I'm pretty sure it isn't the camera. Here are the test factors: K-01, tripod, no filters mounted, 12 second shutter delay, shake reduction off, both with and without hood, both manual and auto focus, "auto" mode, AV mode, Tv mode, night photo scene mode, 30mm, 200mm. In manual mode, I used a full range of apertures, maximum to minimum and in between, along with a range of shutter speeds. I could not achieve detail in any of these, just a white disk. Am I missing something procedurally? Or is it the lens?

Also, with the camera in manual mode, manual focus, and manual lens, isn't the K-01 supposed to ask me to set the focal length?

I wasn't sure how many pictures should be posted, so I used one of the bad ones and the good one with the Nikon

Advice please

Thank you

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07-24-2013, 06:21 AM   #2
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I don't own the K-01, but looking at the second photo, I suspect that you were not using spot metering, which would be why you blew out the moon. Try using spot metering, and I would suggest using manual focus and manual mode so that you can control the exposure yourself and begin with f8-f11 and go from there. Good luck.
07-24-2013, 06:21 AM   #3
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The first seems fine to me. What are the aperture values on those?
07-24-2013, 06:32 AM   #4
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Take some time and compare your shutter speed, ISO and aperture with both lenses. Try the same settings you have on the Nikon, and take another shot at it, then you can compare the two. BTW the moon is not the best lens test subject.

EDIT: Do you have any other shots taken with the DAL55-300, of fixed subjects using a tripod that you can post for us?

http://www.wikihow.com/Photograph-the-Moon


Last edited by altopiet; 07-24-2013 at 07:14 AM.
07-24-2013, 07:48 AM   #5
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there's a discussion from yesterday on taking moon pictures...you might want to look at
07-24-2013, 12:10 PM   #6
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Second shot is badly overexposed, any detail in the moon surface has been clipped to white.

According to EXIF...

With Nikon: 1/125, ISO 400. Aperture unknown because lens was adapted, perhaps you know what you used. Metering center-weighted, because that's all that's permitted with adapted lenses.

With DA-L 55-300: 1/200, f/5.8, ISO 12,800, Metering Pattern (aka matrix or segmented).

Metering the moon is a bit of a challenge, it's like metering a white rat in a coal mine. The camera doesn't know that the only detail you care about is the detail on that very bright spot that consumes only a relatively small portion of the scene and doesn't know that the rest of the scene should be pretty close to black. It guesses that the night sky that consumes a large portion of the sky should be more of an average middle tone and increases exposure accordingly. It's up to you to direct camera. As Brazeal mentioned, spot metering is one way to do this. Another is to chimp the results on the LCD after shooting and decrease exposure with exposure compensation (I think Manual mode is actually a better idea for this) until you see the detail you want in the results.

Reasons why adapted Nikon and Pentax lens exposed differently -- with Pentax lens, there was lots of automated stuff going on that was disabled for the Nikon. Because light was low, camera jacked up ISO to 12,800 (vs. 400, five stops brighter!) and because camera knew lens was at 300mm it increased shutter speed to 1/200 (~2/3 EV darker) in an effort to handle camera shake. Doubtful Nikon lens was f/5.8 but impossible for me to know what it was set to.

Some fundamental info about exposure, there are three contributors:

Time (shutter speed)
Aperture (how much light lens transmits)
ISO (how sensititive recording medium, e.g. digital sensor or film is to light)

Shutter speed typically expressed in fractions of a second. -1 EV as duration of shutter decreases by half (e.g. 1/125 to 1/250), +1 EV as time doubles (e.g. 1/125 to 1/60).

Aperture, expressed in f-stops. Larger numbers mean smaller aperture, less light. -1EV each time f-number increases * 1.4, e.g (f/5.6 to f/8), +1 EV when f-number decreases by same factor (divide by 1.4, e.g. f/5.6 to f/4).

ISO - higher means more sensitivity, more light. +1 EV each time value doubles, e.g. ISO 800 => 1600. -1 EV when ISO number is halved, eg. 800 => 400.

What this means is you get an equivalent change in exposure no matter which of the three parameters you change -- for example, if you double shutter speed # and ISO # simultaneously (e.g. 1/125 f/4 ISO 200 => 1/250 f/4 ISO 400), exposure (tones/brightness) will remain the same.

The automated modes make selecting these easier and often will make a pretty good decision for you but understanding them and how cameras meter will help you know how to fix things that aren't working for you.
07-24-2013, 12:12 PM   #7
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QuoteOriginally posted by Brazeal Quote
I don't own the K-01, but looking at the second photo, I suspect that you were not using spot metering, which would be why you blew out the moon. Try using spot metering, and I would suggest using manual focus and manual mode so that you can control the exposure yourself and begin with f8-f11 and go from there. Good luck.
You are correct on the meter. If timing works out, I'll try spot metering tomorrow morning and update the post.

I did take shots with fully manual focus and settings which also did not yield any detail
07-24-2013, 12:12 PM   #8
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Also, I recommend the book 'Understanding Exposure' by Bryan Peterson. Pretty good at explaining these fundamentals.

07-24-2013, 02:36 PM   #9
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QuoteOriginally posted by Banskojoe Quote
... Also, with the camera in manual mode, manual focus, and manual lens, isn't the K-01 supposed to ask me to set the focal length? ...
No, M mode is still smart enough to detect the focal length of any lens that is capable of reporting it to the camera. If Av and other automatic modes can detect the focal length, so can M mode. There is no benefit to manually entering the focal length unless the lens is incapable of reporting it.

I agree with others who say your 2nd example is heavily overexposed. Here's how I suggest getting started with lunar photography: M mode, manual focus, ISO 800, f8, and handheld. All you'll need to adjust is shutter speed to get proper exposure. After you have some decent shots you can then experiment with those other settings. Why those settings? I'll explain below.
  • Why M mode? Automatic metering is easily confused by a bright moon and dark sky. Advanced metering modes might work but you'll need to learn their quirks later.
  • Why manual focus? Once you get it focused it will stay in focus for a photo session (assuming you don't adjust the zoom - stay at 300mm for now). Recheck every few shots because the 55-300 has a very loose focusing ring.
  • Why ISO 800? Auto ISO is unreliable for the moon because it gets confused by the dark sky. The moon is bright and ISO 800 will probably give you a fast enough shutter speed for handheld. You can adjust the ISO later.
  • Why f8? Each lens has a range of apertures where sharpness is maximized. You can do painstaking tests, or just default to f8 which works pretty well for most consumer lenses like the 55-300. In typical night photography you want a faster/wider aperture to gather lots of light but the moon is a bright object and doesn't really need that.
  • Why handheld? It's easier to change camera settings handheld and you'll be doing a lot of experimenting with the controls. You can add a tripod later after you have some decent shots.
Start with 1/1000s shutter speed. Expect an awful underexposed moon. Slow the shutter speed down and watch what happens. You want the sunlit portion of the moon to be a mix of grays, never pure white and never black.

P.S. You can even practice lunar photography during the day. You'll probably end up with different settings but you'll learn regardless.
07-24-2013, 03:10 PM   #10
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The moon is lit by daylight and should therefore be exposed with close to a daylight exposure value. This one is not the lens' fault :-)
07-25-2013, 06:03 AM   #11
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Good lens Bad operator

Thanks to everyone who coached me to a better understanding of my K-01 and DAL 55-300. I am thrilled with the results

Banskojoe
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