Chromatic Aberations on EX3 question

[Vincent Oliver]

Yes, the Extended edition of Photoshop supports video. It is not the best way of working with video, generally After Effects will be a better choice. However, I supply a lot of 10, 20, 30 second clips to a film library, these short clips work very well in Photoshop, especially as you can apply most Photoshop filters to a clip. I also like the fact that you can use multiple layers, blending modes and Adjustment layers without any great problem. Having said all this, I wouldn't want to produce an Epic movie using just Photoshop. Once finsihed editing you can use the File > Expot > Render Video to output your file.


See instructions for using video in Photoshop in my previous post on this thread.

[David C. Williams]

Originally Posted by Steve Phillipps

Stopping down doesn't mean you're using more of the centre of the image, only using a smaller sensor would do that.
Steve

It does.

YouTube - Chromatic Aberration and Aperture Size

[Steve Phillipps]

How does it David? The light is being taken in through the whole of the lens and only passes through the aperture blades at the rear element where it is focussed.
Surely if you're only using a central portion of the lens then you'll get a magnifying effect as you do when using a small sensor.
I'm not an optics expert I admit, so maybe I'm wrong.
I think the link you provides demonstrates longitudinal chromatic aberration, which is affected by aperture, it's translateral that causes colour fringing. Again, I'm no expert though!
Steve

[David C. Williams]

Longitudinal also causes CA. As I said, "stopping down does help somewhat". Transverse can cause registration errors, which can be alleviated in cameras with CA processing, or in post.

As I also said, stopping down does cause the outer portions of the lens to not be used. Go argue with Penn State Uni, that's their video I posted.

[Steve Phillipps]

Originally Posted by David C. Williams

As I also said, stopping down does cause the outer portions of the lens to not be used. Go argue with Penn State Uni, that's their video I posted.

I can't really argue, as I really am no expert as I said.
One thing that springs instantly to mind though is that if stopping the lens down reduces the amount of the lens being used this would mean that you could use for instance APS-C sized stills lenses on full frame bodies if you stop them down enough as you won't get vignetting as you're not using the outer edge of the lens. But this is not the case AFAIK.
Steve

[Vincent Oliver]

The one thing that is not pointed out is that you are changing the colour and not actually removing the fringe. On my example shots posted earlier on this thread, I was left with a grey halo. Although I did change the grey to a sky colour, using the "From > To" feature. The end result on my footage was far from ideal, in fact the Electricity cables just looked too thick in places due to the replaced colours.

Photoshop and the Lens Correction filter gave the best results for my shot, as the colour channel was actually shifted to bring it back into register. However, on some other scenes with a less prominent sky backdrop, After Effects produced a good result.

[Mark OConnell]

I was unhappy with the Change to Color results the first time I tried it as well, but after spending more time with it I found I could get very good results. Remember to set Change to Hue & Saturation. I've found that useful numbers to start with are: Hue 20%, Lightness 5%, Saturation 5%.

FWIW-

[Vincent Oliver]

The change to colour works well with some subject matter, especially if it is against a dark backround, but when it comes to tree branches and other fine detail against a light sky, then the whole thing falls appart. Thanks for the tips all the same.

There is realy no substitute for a good quality lens. Here are two examples. One was shot at the full zoom setting on the Sony stock lens, the other was shot with a 85mm Nikkor using Steve Schovlars Adaptimax adaptor. Look at the left edge of the pictures. Click on the images below to open them, then click on the image again to view at 1:1 magnification. The difference speeaks for itself.

[Alastair Traill]

The differences between Nikon and Fujinon are impressive. I would be very interested to know if the lens file for the Fujinon is set to its optimum. The menu provides for adjustment capabilities but so far I have not seen an account of the best way or even any way to effect the procedure. Even the local Sony repair centre cannot offer assistance.

[Vincent Oliver]

I haven't touched any of the lens file settings other that doing an Automatic Back Focus from time to time.

The Nikon lens used is the old style manual Nikkor, i.e. not the rubberized grip type. I have a whole set of Nikkor lenses ranging from 20mm through to 500mm, you can pick these lenses up for a song on e-bay or other sites as most people want auto focus and up to date lenses. Optically they are still superb lenses as you can see in my sample.

The stock lens at full magnification is roughly equivalent to the Nikkor 85mm.

[Mark OConnell]

I'm a massive fan of the old Nikon lenses. The more I shoot and learn, the more I appreciate the importance of the glass. I looked at an old 600mm f4 the other day, a monster, 14 pounds of metal and glass, the image it made was beautiful. But, I moved from my EX1 to an EX1r instead of an EX3, mainly because of the form factor, so my only option for more reach is an extender. I have to be very conservative with it. If I push it in terms of the lighting or contrast of a shot I'm pretty much guaranteed CA, I can usually fix it in post but not always. Not an ideal situation. My next camera will definitely allow for changing the lens.

[Alastair Traill]

Quote: - I haven't touched any of the lens file settings other that doing an Automatic Back Focus from time to time.


Hi Vincent,

I am not suggesting that you have changed any of your lens file settings but no doubt since you have owned the Fujinon it has been subjected to normal usage that may have detracted from its performance. No doubt there is some wear of threads, cams and other components that do the internal adjustments hence my interest in whether or not its lens file settings are still set to their optimum.

I have not looked very closely at my own EX3 but have got as far as noting that the Fujinon lens file can be recalled and I assume that the settings can be readjusted if deemed necessary.

However I have looked at the finder image when using a Nikon lens and tweaked the flare settings. As I did not see anything happen I returned the settings to their original levels. Since then I have been trying to find a good procedure for using this interesting feature of the EX3, I am sure that Sony must have good reasons for including it. For a start what does one need to display the EX3 image directly on to a high resolution computer screen?

[Vincent Oliver]

I had only just got the Stock lens when I shot the footage examples so no wear and tear - this lens was a replacement to my first lens which unfortunately tried to mate with a concrete floor.

I too am rather puzzled by the numerous adjustments that are available, I don't even understand what half of them are supposed to do. I just try to shoot everything as clean as possible and then adjust colours etc. in post.

For my editing work I use Adobe Premiere CS4 & CS5 on a system that has a Matrox RTX2 card fitted. I use a 24" Samsung SyncMaster 245a as my working screen, i.e. the application interface etc. and a Samsung 24" SyncMaster T240HD for true High Definition monitoring, The Matrox card provides the HD signal. I also have a JVC 15" studio monitor for final colour correction, although I find the Samsung HD monitor does a good enough job on this.

[Alastair Traill]

I don’t pretend to know what all the lens file adjustments are. However I assume that they are provided so that one can get the best results possible from any particular lens. If the lens is set to its optimum this could well save time in post.

It would be also interesting to know whether the same lens file is used for all the standard EX3 Fujinon lenses (for example) or whether an individual file is prepared for each lens in the factory. If it is the latter the file may need to be modified if a replacement lens becomes necessary.

[Vincent Oliver]

Interesting you say that Alastair, I do have two lens data files on the camera, under Recall, VCL-614B2X and XS8X4AS-XB8. Do you or other users also have two files under the File > Data > Recall section?