Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
12-18-2009, 10:00 AM   #1
Senior Member
patriotap's Avatar

Join Date: Oct 2009
Location: South Jersey
Photos: Albums
Posts: 159
2nd try

took all your advice from this post:
https://www.pentaxforums.com/forums/pentax-beginners-corner-q/78253-finally-t...y-new-k20.html

and tried again, now i seem to have gone to far the other way, im getting closer i think, what suggestions can you all give me?

Name:  boston.jpg
Views: 288
Size:  69.3 KB

12-18-2009, 12:46 PM   #2
Veteran Member
miss_alexx's Avatar

Join Date: Nov 2009
Location: Montréal, Québec
Photos: Albums
Posts: 584
That is a lot better than your first one ! What are the settings you used for this one?
12-18-2009, 04:06 PM   #3
New Member
hoshinokoe's Avatar

Join Date: Oct 2009
Location: california
Posts: 14
Wow that is look really good buddy. I know that I, personally, would love to see this cityscape right after sunset - giving the sky some nice deep purples... well depending on the weather lol
12-19-2009, 12:38 PM   #4
Senior Member
patriotap's Avatar

Join Date: Oct 2009
Location: South Jersey
Photos: Albums
Posts: 159
Original Poster
QuoteOriginally posted by miss_alexx Quote
That is a lot better than your first one ! What are the settings you used for this one?
thx used my MF A-50mm lens with f13 and iso 100 15s shutter speed


Last edited by patriotap; 12-19-2009 at 12:46 PM.
12-19-2009, 12:40 PM   #5
Senior Member
patriotap's Avatar

Join Date: Oct 2009
Location: South Jersey
Photos: Albums
Posts: 159
Original Poster
QuoteOriginally posted by hoshinokoe Quote
Wow that is look really good buddy. I know that I, personally, would love to see this cityscape right after sunset - giving the sky some nice deep purples... well depending on the weather lol
lol well speaking of weather, it was 10 degrees with 20mph winds, and i took this in about 1 minute! I ran out setup took the shoot and ran back to the car!!!
12-20-2009, 07:10 PM   #6
Loyal Site Supporter




Join Date: Jun 2009
Location: Tumbleweed, Arizona
Photos: Gallery | Albums
Posts: 5,107
Hi Brian, That is a tremendous improvement!!! I might suggest that on the settings that you provided, that you really did not need to go to f13. The ISO 100 was very good, even though it will extend the shutter time, the image quality increases a lot.

I don't have the information for your exact lens, however I think that you can use the data from the FA 50/1.4 pretty safely. Take a look here ...

Pentax SMC-FA 50mm f/1.4 - Review / Lab Test Report

You can also see...
http://www.dpreview.com/lensreviews/pentax_50_1p4_p15/page4.asp

In the second link, play around with the aperture to get the maximum "blue" and that happens around f4. Different testing method - but I think you can be pretty sure that f4, f5.6 somewhere around there would be the sweet spot for your lens.

Scroll down to MTF resolution and you will see that the lens maxes out at around f5.6 (essentially both the center and the edge - although you give up a bit on the center - you essentially want to max the entire lens). Also, f8 would not be bad either.

Now you want to make sure that everything is in focus. So go check this out...

Online Depth of Field Calculator

Enter your camera type, with 50 mm, and f5.6 and take a guess for panoramas of say 100 feet. You will see that with those entries, everything from about 45 feet to infinity is in focus.

So, use f5.6 and manually focus at 100 feet on the lens (turn the lens to about 100 feet), and then go from there for the shutter speed. It looks like you nailed the shutter speed just fine.

That should give you a bit more leeway so that your not having to stop the lens down as severely as you used this time.... there by reducing your shutter times.

Wonderful picture.....

Last edited by interested_observer; 12-20-2009 at 07:18 PM.
12-21-2009, 07:52 AM   #7
Senior Member
patriotap's Avatar

Join Date: Oct 2009
Location: South Jersey
Photos: Albums
Posts: 159
Original Poster
the lens is a Pentax SMC A 1.7/50 and i took a look at that 2nd link and wow, ill try and figure that all out! Thanks for your help
12-21-2009, 09:12 AM   #8
Loyal Site Supporter




Join Date: Jun 2009
Location: Tumbleweed, Arizona
Photos: Gallery | Albums
Posts: 5,107
Morning Brian, For night photography (at least for me) its sharpness and focus. Sharpness does not count unless the item is in focus. So the above process is to easily find the fstop where the lens is sharpest, and preset the focus to be the best you can get - or there a bouts.

When your SMC A 1.7/50 was made, no one did any quantitative tests and published them as they do today - it was essentially field trial and error. So the links will be somewhat close to your lenses' capabilities, and should be close enough. I have the same lens that I picked up about 18 months ago for a song, and it works well.

The next item is focus, and what is being done here is using the hyper-focal distance of the optical design of the lens. Essentially prefocusing for a distance of around 100 feet. The focus scale of the lens is approximated, so its not infinity, but something less (just back off from infinity a bit). Using the verier scale of the lens, you are just going to have to guessestimate there, but it should be ok.

On the second link -
Pentax SMC FA 50mm F1.4 Lens Review: 4. Test results: Digital Photography Review

... you just want to take your mouse and click holding it down in the aperture window sliding the values back and forth trying to get the upper curve to be the highest you can. That is around f5.6 and the color is blue. You can see the color scale over on the left. Also you can see that they tested the various areas of the lens, so you want to get as much blue across the entire lens surface as possible.

The first link does the same thing, just expressing the information in a different way. Same idea, you want to maximize the resolution.

Now to be fair, the only thing that really counts is the final product, and that is you out where ever taking a picture that you are happy with. All this is doing is to take the information from a lab, available here on the web and trying to apply it in a way such that we can come up with something of a simple process to help make taking pictures a bit more fun and ensuring that the finished product is near the expectations we have.

Plus, you really do not have to remember much - write it down. Take a 3x5 card and for each lens just jot down the information...

-- lens -- fl ---- fstop - hf dist
12-24 18mm f5.6 40 feet
50 ----------- f5.6 45 feet
etc.

For zoom lenses like the 12-24, I also use the information to figure out what focal length is the sharpest for the lens, hence 18mm at f5.6. (note- I used the Tokina 12-24 information for the Pentax DA 12-24 since dpreview had the Tokina information and not the Pentax. They are essentially the same lens - or close enough for this.)

Also, for most lenses the sweet spot is around f5.6 to f8. So if you forget or loose the card, guess at around f5.6 to 8 and you should be close enough. And if guessing on where to dial in 100 feet is difficult, pick something 100 feet away and focus on it in auto focus and then flip back to manual and you should be ok.

12-21-2009, 09:06 PM   #9
Veteran Member




Join Date: Apr 2007
Location: Melb. Aust
Posts: 841
QuoteOriginally posted by hoshinokoe Quote
I know that I, personally, would love to see this cityscape right after sunset
yep... take it in the window after sunset and before 'night'
12-25-2009, 09:43 PM   #10
Senior Member
patriotap's Avatar

Join Date: Oct 2009
Location: South Jersey
Photos: Albums
Posts: 159
Original Poster
thanks guys great in depth stuff that Im going to have to read up, still just starting out and lots to learn!
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, pentax help, photography
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
2nd Body wjt Pentax DSLR Discussion 14 10-17-2010 04:39 AM
2nd amendment jct us101 General Talk 15 11-17-2009 11:42 AM
People 2nd Prize eccs19 Post Your Photos! 7 10-28-2009 07:59 PM
People 2nd Wedding creoleart Post Your Photos! 10 10-04-2009 11:08 AM
Need a 2nd body die444die Troubleshooting and Beginner Help 10 04-24-2009 01:41 PM



All times are GMT -7. The time now is 12:25 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top