Lens problem? Highlights 'glowing'

steve.82

steve.82

Messages
438
Edit My Images
Yes
Well, had my first day in anger with an SLR yesterday (400D bought from here :clap:)

So much better to time the shots well now! However I think the lens I'm using is causing problems. Pretty sure it's nothing to do with the body as I have another lens with knackered electronics that doesn't suffer the same problem.

Lens is an EF 35-70 and all looks to be in order. Judging by the crops below though something's amiss... any ideas chaps?

IMG_6450.jpg

IMG_6450-1.jpg
 
I'm a bit confused, what exactly is the problem you think you have?
 
Particularly the sky bleeding out over the black helmet. One side I could understand (complimented by a red fringe on the other side, not blue both sides), and could correct in software, but both sides? Also if you look at the pink bridle, it's almost glowing and lighting up the dark horse around it. Looks not right to me! Particularly as a kit lens with no electronics doesn't exhibit this at all.
 
If you are refferring to the colour of the jacket and reins then your saturation/vibrance seetingsd in camera may be too high.

If you shoot jpegs the above may apply if raw then it would be doen to the pp on computer afterwards.
 
Shot raw, same artifacts before any PP

edit: and the jacket really is that bright... scary stuff!
 
well there is some purple fringing and general lack of sharpness.., then again this is a 20-year old kit lens!
 
pearce_jj said:
well there is some purple fringing and general lack of sharpness.., then again this is a 20-year old kit lens!
Click to expand...

hmmm likely to be things going out of tolerance then? Can't see a strip and clean helping that
 
How rude :bonk:

I'm not too worried about the lack of focus, just the purple fringing and glowing pink parts.

It is a 100% crop, as said above, maybe it is just too old and wobbly...

It attains a similar level of focus on stationary subjects
 
To be honest it's not the best shot to draw lots of conclusons from, as the subject where the problems are occuring is obviously moving. My thinking that some of this could just be caused by mottion blur, and I see that the lens was at f4.5 (I don't know what the lens was but if it was wide open at 4.5 it woun't be as sharp as the lens can do). Take some static shots and see if you can replicate the problem would be my advice.

ps, Is your monitor calibrated? that could be another thing to look at.
 
The lens just isn't good enough to view at 100% on a digital camera and expect it to be pixel perfect. If you want that then the 24-70 F2.8L will be the way to go..., with a very large price tag though!
 
i think its jsut the lens and its showing its age, remember when lenses were designed in those days it was harder to get them perfect than it is now.

you are also severly testing the lens when analysing it at 100% which is very rarely ever gonig to be printed/view at such a resolution.
 
This forums relentless! Thanks for the help and comments everyone!

Doubt it will be blur, shutter speed was over 1/1000 and yes aperture was wide open, could be an issue.

Hmmmm, anyone got a cheap EF-S mkII kit lens spare, as I'm quite happy with the image quality from that (at the moment at least... I know many of you don't rate the kit lenses but I am just beginning...)

As for screen calibration, yes I could do with doing that. Is it something you can change systemwide? (Windows 7 on a laptop screen)
 
There's a wizard for it in Windows 7 from the display control panel.

Kit lenses come up on eBay for about £30 IIRC.
 
It's called chromatic aberration (or colour fringing) it's caused by the lens not focusing all the colours properly, usually worse on cheap badly corrected lens, but it can be a sign of a faulty or damaged lens as well.
Photoshop has a tool designed to help remove it, filter/distort/lens correction that and a bit of dodging/burning and it's easily fixed.
 
And Lightroom has a slider called chromatic abberation which does just that.. takes away magenta or blue or green from your edges. (y)
 
CA becomes far worse in the corners and out focus areas. Canon 24-85mm f/3.5-4.5 or 28-105mm f/3.5-4.5 are much better and cost around £100 used. The sharpness is slightly behind extremely more expensive L, they are a tad slower but still relatively fast. However on FF they are not so good (compared with 24-70 on eos 5 film), but with 400D will be fine for a start. Colour, contrast and CA can be easily fixed in Lightroom and only takes 30 seconds to do. While I am fairly happy with my 24-70mm I can hardly justify the price I paid (I mostly use it at f/8 btw)
 
Looks like I best get saving!

edit: and thanks again chaps, very helpful stuff.

As for CA, is it possible for it to be blue on both sides of an object?
 
steve.82 said:
Looks like I best get saving!

edit: and thanks again chaps, very helpful stuff.

As for CA, is it possible for it to be blue on both sides of an object?
Click to expand...

There is another one called spherical aberration. It can not be corrected but I am not sure if I can see it in that photo.
 
It just looks like what I'd expect from cheap end lenses.
It might be 20 years old, but was it much better brand new...:shrug:
 
The lens in my old Minolta A200 does a much better job, so I would hope so!

I would imagine the EF-S lens I have with pooped electronics is newer but aimed at the same market as this lens here, and that's much much better than this.
 
I don't know anything about Canon lenses, but in the Nikon line up, you get what you pay for, age is not often an issue.
Maybe its a combination of not great glass/age/miss-focus, or maybe some cheaper lenses are better than others..
 
Yes I guess if the manufacturing tolerances aren't that great chance will dictate that some are decent and some not so. Hmmmmm, might get a stash of entry level lenses and keep the best one...
 
I'm not sure the image is that bad considering. It's an old lens that was hardly stellar even in its day. Shooting a very dark subject against the light like that is quite testing, especially at a low f/number for that lens. Is the lens perfectly clean? A smeared finger print can wreak havoc with flare.

The newer IS version of the 18-55 kit lens is very good, and great value. And if you download the latest version of Canon's DPP Raw software (free upgrade here: http://web.canon.jp/imaging/dcp/firm-e/pssx1is/index.html ) you can sort out CA, vignetting and distortion from the aberrations correction suite. It picks up all the lens settings from the file data and applies custom corrections with a mouseclick :)
 
Quite possibly not... what can you use to clean them? Would a glasses (spec) cloth do the trick?
 
daugirdas said:
There is another one called spherical aberration. It can not be corrected but I am not sure if I can see it in that photo.
Click to expand...

I think my sigma 400mm suffers from spherical abbs, giving a sort of softened effect at areas of high contrast / brightness. IIRC soft focus lenses use controlled amounts of spherrical aberrations and the effect does seem to be similar.

To me it looks like the problem is most apparant on the rider's cuff in the posted photo..
 
Yep, certainly does it there! In amongst the sky creeping in on everything (and the pink jacket out into the sky)
 
Tried it in similar conditions at f9-f11, much improved! Would be nice to have decent quality with larger apertures though...
 
All lenses have a sweet spot, and most this is when the lens is stopped down 2 or 3 stops, this includes expensive lenses but the difference is not so noticable.
 
That lens was never designed to be good wide open.
Things like lack of focus and camera shake ( yes even at 1/1000)
Just show up the problem more.

Digital sensors show fringing far more than on film cameras and lens designers did not put it at the forefront of the criteria then.
In the long run a faster focussing and better lens will make heaps of improvement.

Even the cheap 18-55 kit lens will give better results than these, even when blown up to compensate for the shorter focal length. It too has some fringing but not much at 55mm.
 
Certainly some fringing in the 100% crop.

This shot would techically chalenge most short lenses, you are quite far back, using lens wide open and at long end, shooting a fast moving dark subject against a bright sky. Also the 400D is a geat little camera but it is not a specialist sports camera.

Pixel peeping is not always helpful.
 
Pixel peeping? What do you mean, being overly picky about such things?

I could do with the wider angle of the kit lens (or lens with similar range) too, and with the lens arriving tomorrow (55-200) will hopefully compliment it a bit more usefully.
 
steve.82 said:
Pixel peeping? What do you mean, being overly picky about such things?

I could do with the wider angle of the kit lens (or lens with similar range) too, and with the lens arriving tomorrow (55-200) will hopefully compliment it a bit more usefully.
Click to expand...


Pixel peeping is when you zoom in on the image on the computer to 100% and more, you will see problems, that when printed are not always as much of a problem that you think they might be.
 
You must log in or register to reply here.
Back
Top