suman Posted October 16, 2004 Share Posted October 16, 2004 I am the owner of this lens for the last two days and posted a different question on my setup yesterday. Here is what I have found with my test for CA. Set a can of MD in my windows side under cloudy skylight condition. Took the photos from my D60 mounted on a tripod, AF/AE with manual release. Check out the attachement. What I found is that that the photographer has to be very carefull with highlighted areas at higher aparature values. Stopped down is better, much BETTER.<div></div> Link to comment Share on other sites More sharing options...
suman Posted October 16, 2004 Author Share Posted October 16, 2004 Forgot to mention, this result is after correcting for CA with value of +100 in each direction in PSCS RAW converter. Link to comment Share on other sites More sharing options...
grant_. Posted October 16, 2004 Share Posted October 16, 2004 one problem is your way overexposed.....learn how to expose a digital image and youll have far less problems... Link to comment Share on other sites More sharing options...
andrew robertson Posted October 16, 2004 Share Posted October 16, 2004 Another problem - moving the CA sliders to 100 will make the CA MUCH more pronounced. You should only move each slider far enough to correct the CA. Moving it farther just creates more CA! Link to comment Share on other sites More sharing options...
chiswick_john Posted October 16, 2004 Share Posted October 16, 2004 Way too much exposure - not sure if this is CA at all. The only way to correctly identify CA is to flick between the colour channels in PS and see if the image registration moves - if it does you have CA - if it's perfectly registered you have sensor blooming. Link to comment Share on other sites More sharing options...
tommyinca Posted October 16, 2004 Share Posted October 16, 2004 Sorry I have no answer but a question. Have you try ND or CPL filters to cut down the light with out stoping down and see if it help. I was wondering if this is not CA but light reflecting on back side of the lens and causing problem. Link to comment Share on other sites More sharing options...
jbq Posted October 16, 2004 Share Posted October 16, 2004 Leave the image uncorrected in the raw converter - you may end up doing more harm than good if you play with parameters too much. Link to comment Share on other sites More sharing options...
suman Posted October 16, 2004 Author Share Posted October 16, 2004 Is it really overexposed? I don't think so. Check the actual image. Metering mode is evaluative.<div></div> Link to comment Share on other sites More sharing options...
suman Posted October 16, 2004 Author Share Posted October 16, 2004 And here is another without any CA correction in PSCS.<div></div> Link to comment Share on other sites More sharing options...
grant_. Posted October 16, 2004 Share Posted October 16, 2004 def overexposed...no detail in the top Link to comment Share on other sites More sharing options...
suman Posted October 16, 2004 Author Share Posted October 16, 2004 Was on the can, I mean the front wall of the can. I think that was the reason the photo is not showing the details of the background. Am I wrong Grant? Link to comment Share on other sites More sharing options...
suman Posted October 16, 2004 Author Share Posted October 16, 2004 Also I forgot to mention, everything behind the can is actually through the glass window, so fuzzy with all the reflections from inside/outside. Link to comment Share on other sites More sharing options...
bob_bell Posted October 16, 2004 Share Posted October 16, 2004 I think what everyone is saying is that you are looking for CA in an area with blown out highlights and it is overexposed. If the tops of soda cans werent satin finished you would have a really bad hotspot on the top. Go shoot something other than cans in your window sill and look for CA. It will probably be there on strongly backlit subjects. Link to comment Share on other sites More sharing options...
jbq Posted October 16, 2004 Share Posted October 16, 2004 Doesn't look like CA. Overexposed, yeah, but not really CA (there's little risk of CA being significant in the center of the frame, look for it in the corners if you're after it). Link to comment Share on other sites More sharing options...
suman Posted October 16, 2004 Author Share Posted October 16, 2004 Thanks folks. I am not after it, it just popped up to my eyes and that's why I was trying to figure out. Link to comment Share on other sites More sharing options...
andrew robertson Posted October 17, 2004 Share Posted October 17, 2004 it also helps to underexpose a bit or use the partial meter on a subject such as a can. I find sometimes it's easier to meter a highlight and give it +1 2/3 stop to make it close to white, but not overexposed. You should really shoot with the review setting switched to On (Info) and check when you're shooting periodically for blown highlights as well. You don't have to pay attention to them once you have decided what range to expose for, and if you wish to keep whatever you're shooting from blowing out. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now