Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
05-14-2013, 03:32 PM   #1
Forum Member




Join Date: Dec 2012
Posts: 75
Some questions about metering and greyscale

Hello all,

I had some questions regarding the K-o1 and, maybe this is more a general question about technique, but I am using only the K-o1 and so it makes sense to me to frame in that way. Also, I should mention that I am using FW v.1.03 and Picasa for post. Part of this inquiry is for me to try and understand how much mitigation of "issues" I can expect to resolve in post, and how much should I customize the capture settings in-camera in order to compensate for my (unfortunate) choice of post-production tools, which is the only thing I can run reasonably on my current computer (a netbook)... Okay...here goes:

--Spot Metering: I am finding that I can get a much better exposure if I spot meter the brightest area in the frame and then use the resultant shutter speed in Av mode (or sometimes a stop or two one way or the other), usually I will meter, recompose, then set exp. manually. Sometimes, if I am shooting street scenes, I try to determine on the fly what the brightest thing in frame is and center it (which has consequences compositionally), get reading, snap photo, crop composition in post. Sometimes this works, other times it leads to way underexposed areas that clip to black very quickly especially if converting to B&W in post. I am wondering if it is Picasa (I have been able to bring out midtones that looked completely clipped in the trial version of DxO O.P. 8, so I am thinking that there is something about Picasa that has a more limited range than what was actually captured?). I could use some pointers in regard to the (two available for manual lenses) metering modes on the K-o1 -- spot and center weighted. Matrix (full scene) metering with the 40 XS, I am not really very well versed in, but seems like it would exhibit more of the 'drawbacks' of center weighted metering (lower shutter speed requiring higher ISO or use of stabilization device) and a tendency toward blown highlights.

--B&W conversion: If Leica's press-kit for the monochrom M is to be believed, you lose a third of your resolution if you convert to B&W. Anybody know exactly the number of steps between black and white (I think of things in terms of oil painting..so I am thinking about chroma and its relative value on the musell greyscale. For instance violet is nearly black on the munsell grey scale when it is at full chroma/saturation. I may be wrong, but this would seem to make sense as to why you can get those really contrasty, almost black skies with a red filter (blue +red = violet)) that the K-o1 is capable of? I saw in another recent post that it comes out to at least 11 or 12 EV steps (please clarify this...what exactly is an EV step?). My suspicion is that I am loosing resolution by converting and loosing my range of values by using Picasa's rather hamfisted approach to contrast adjustment.

--Use of 'Contrasty' v. "Neutral" lenses and in-body compensation/custom settings: I have a theory, and I wonder if I am thinking about it correctly, that if you try to minimize overall contrast in-body, you will have more lateral headroom in post production in terms of range of values, provided you are within the middle of the range and not too far to one side or another of the histogram. I have been using as my primary lenses the 50 f/1.7 "M" and very recently the 30mm f/2.8 "K" which I have found to be contrasty and neutral-ish respectively. Which is kind of strange, because I seem to be getting the opposite result of my theory. I seem to get more lateral freedom with the 50mm than the 30mm. Particularly, darks seem to clip and 'grow' into mush a lot more quickly than with the 50mm. Now, it did occur to me that contrasty could mean not just high-key, but wider range of values. In any case, is there anything that can be done to affect the DNG in order to open up a full range of black and white values in-camera? I have almost given up on the idea that Picasa will ever be very good at anything other than very large adjustments of black and white. Also, it seems that Picasa tends towards a rather 'soft glow' in the highlights, which I find somewhat annoying. Maybe its my negative, maybe its picasa's algorithm for looking at DNG files....I am not sure. Anyone?

In any case, I appreciate any feedback on these issues and value the input.

Thanks!

Greg

05-15-2013, 02:43 PM   #2
Pentaxian
Transit's Avatar

Join Date: Aug 2007
Location: Whanganui NZ
Photos: Gallery | Albums
Posts: 4,075
Bump

... your interesting questions might more likey attract answers
in a more general forum category ?
Pete
05-17-2013, 05:07 PM   #3
Veteran Member




Join Date: Dec 2012
Photos: Gallery
Posts: 696
@cristigj -- for editing. I use Oloneo Photoengine and Xara Photo & Graphic Designer on a little Acer netbook... no problems.

You're on the right track with spot metering, and exposing for the highlights... or the area where highlight turns into normal lighting. In Oloneo, you can apply mild HDR (increased TM Tone Mapping) with increased Details to add punch to the image. Oloneo also lets you selectively increase the saturation or brightness of different colors -- like red, green, etc. For B/W, you just decrease the image color Saturation all the way... but the adjustments for the different colors still work and affect the B/W picture. Oloneo works fine with Pentax RAW files... but also with JPGs, which I prefer for simplicity.

Xara lets you quickly add layers that affect one another. For instance, you can copy an image on top of itself, then apply Transparency > Linear > Stained Glass to selectively darken, say, a sky area while leaving the rest of the image undisturbed. More Xara photo tips at the Xara-Users forum (I wrote them... it's a great program).

Free? Go to getpaint.net ... and get the superb free photo editor you'll find there. It has layers and gradients. Lots of support, and free plugins... follow the links.

Also, for B/W, get B/W Photostyler from thepluginsite ... all the help you need to get that red-filter effect, or film effects like simulating Tri-X grain. Another neat small program... here's a recent photo, used the Orange filter and #4 Hard development...
Attached Images
 

Last edited by jon404; 05-17-2013 at 07:16 PM.
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!
center, contrasty, frame, k-01, k01, lenses, mirrorless, pentax k-01, picasa, post, range, sense, values
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Questions about some lenses PenPen Pentax SLR Lens Discussion 6 04-12-2012 12:22 PM
Some questions about geotagging and gps tracks AquaNox Troubleshooting and Beginner Help 2 02-02-2012 11:28 AM
Some questions about P-TTL and Pentax flash generally... jeztastic Flashes, Lighting, and Studio 7 12-29-2011 06:40 AM
Questions about using M42 lenses - focus and metering Spodeworld Troubleshooting and Beginner Help 23 10-12-2011 10:01 AM
Hello, and I have some questions about low light shooting strictlypentax Welcomes and Introductions 2 06-02-2007 09:30 AM



All times are GMT -7. The time now is 11:42 AM. | 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