Photography Thailand Forum

[Marc Schultz]

Today I had an experience with two Canon L Lenses which practically made me fall on the floor.

I was shooting some photos in the studio on a white background with 5 studio lights and a piece of white acrylic (Perspex) underneath the models for a bit of a drop shadow reflection.

At first I started shooting with the Canon EF 135mm f/2.0 L USM Lens since it is known as one of Canon's sharpest primes.

The pictures looked so washed out and low contrast I couldn't figure it out. I checked all my lighting and all seemed OK so I figured I was getting some lens flare which was softening the contrast a bit, but actually I wasn't.

Maybe a bit too much bounce from the acrylic on the floor, but not enough to where it should make the contrast of the photos drop so much.

I then stopped shooting and played with a few of the shots in Photoshop to see if they were repairable and realized I could more or less fix the contrast problem in post, so I just kept shooting with the 135mm lens.

Finally I had to switch to a slightly wider angle lens to accommodate the position of the models as the Canon EF 135mm f/2.0 L USM Lens was too much telephoto for the shots in general. So I switched over to the Canon EF 24-105mm f/4 L IS USM Lens to allow myself more versatility on focal length.

Immediately the contrast and colors improved tremendously. See for yourself. I have done no processing on these images. They are straight out of the camera.



The image from the prime lens might be just a mosquito hair sharper, but the general conclusion is the Canon EF 24-105mm f/4 L IS USM Zoom Lens in this case has better contrast and colors than the Canon EF 135mm f/2.0 L USM Prime Lens. It hardly makes any sense to me!?!!?!?!?

[mahonyWeb]

Wow!

Having owned both of these lenses I'm very surprised by this. The 24-105 is no slouch, but my 135 was a really exceptional optic - unbelievably sharp with great contrast.

How old is your 135? Have you considered having Canon check it out?

[Marc Schultz]

Thanks Mahony. You got me thinking a bit now. The lens is only 14 months old and probably been used only a dozen and a half times I would guess. It stays in the dehumdifying cabinet when not being used as well, so it seems unlikely it would have developed a fungus problem. I probably will have Canon take a look at it, but I held it up to the light and can't see any problems with the clarity of the lens elements itself.

The haze on this series of photos might be coming from the strong light being thrown on the white background which could be bouncing back into the lens. The 24-105mm might be less sensitive to lens flare than the 135mm lens, and thus there is no drop in contrast from the light bouncing off the background when using the 24-105mm. I did have the light on the background hitting it at about 1.5 stops more than what I was shooting the lens at in order to completely blow it out.  

I do have a cheap Japanese Marumi UV Haze filter on the 135mm lens for protection, but I doubt that would have any affect. My 24-105mm lens has a filter on it as well, but it is a Hoya Protect filter which has no UV protection film on it, but again I doubt the filter makes any net difference. I will probably change the filter on the 135mm lens now to be a protect only filter as well (minus the UV protection), but I don't think that is going to make any difference.  

Once discovering the issue, I actually decided to re-shoot all the shots using the 24-105mm lens that I originally shot with the 135mm, but somehow I missed one of the shots. Despite all the problems with the 135mm lens, I was able to adjust the RAW file to pull enough contrast out of it (see below) to salvage this one image. I still prefer the 24-105mm shots though.

[mahonyWeb]

I seldom use UV filters, unless I'm shooting at the beach or the subject is my daughter (who loves reaching for the front element) or our pet dog. I'd definitely remove the filter, especially if it's a cheap item.

Do you use the supplied lens hood?

[Marc Schultz]

Thanks, but you would be surprised how many times a bang taken by a protective filter has saved a lens of mine from being smashed or scratched. I can show you dents in the rim of some of my filters and I smile every time I see them thinking how I am glad that it wasn't my lens taking the hit. Anyway, yes, full length factory hood.

The cost of the filters doesn't matter much when it comes to these clear glass filters I have found. Clear glass is clear glass basically. Keeping it clean is the key. The UV coating actually only usually helps to cut out stray light (on or off the beach) and doesn't change the colors of your photos any. It should actually help with lens flare, but didn't this time obviously.

This is a good and cheap protective filter made by Hoya that I have on a few of my lenses now:

http://cgi.ebay.com/HOYA-72mm-72-PRO1D-PRO1-D-Digital-Protector-Filter_W0QQitemZ220586676469QQcmdZViewItemQQptZCamera_Filters?hash=item335bfd90f5

Canon makes their own protect filter for double the price. I like these Hoya ones though because of the thin frame which is better for wide angle lenses. The Canon ones are a bit thicker, but I have a few and they are good too.

[Ray Evans]

I can't trace the thread but some time back on another forum a contributor conducted a very serious evaluation of filters on digital sensors and concluded that even the best Schott glass ones were degrading the image and reducing contrast and sharpness.

In this context it appeared that the longer the focal length combined with a wider aperture, the greater the degradation due to the light gathering aspects of such a lens.

He went through a range of "glass" filters (ignoring the obvious plastic ones) and found the Heliopan and B+W Pro line as being the lesser of the culprits.

Of course, the problem is that a lot of the Canon units require a filter to conclude on weather sealing and the above filter range is so expensive as to almost equate to lens cost!

Seems we can't win.

Personally, I keep a protective filter on all my lenses and if absolute detail is required (as opposed to hand held street stuff) I remove the filter for the shot.

[Marc Schultz]

That's great information Ray, thank you. I think in the future I will simply remove my filters on all studio shoots, but probably keep them on for outdoor shooting.

[Marc Schultz]

I did another studio shoot with the 135mm lens yesterday and no problems with color and contrast. So I don't think there is a problem with the lens. I think it is just really sensitive to back light and lens flare. More sensitive than most Canon L zoom lenses. So something to be more careful of in the future. I also removed the filter yesterday when shooting just to be sure that it wasn't a problem. Thanks everyone for their input on this issue.

[Adzz]

Hi Mark,
I think I would have put it down to flare from the lighting set up myself. The light flies in from everywhere on a set like that if you don't have it well flagged off.
Anyway, like you said at the start of the thread, easy fix in photoshop these days.
Regards Adam

[Marc Schultz]

Thanks Adam. Still yet the one I fixed in Photoshop doesn't quite compare to the colors and contrast of the ones taken with the other lens which wasn't so affected by the light bouncing off the background. So yes, Photoshop does a great job, but sometimes I find it hard to repair what was less than perfect to begin with unfortunately. At least its passable though :)

I do believe everything was flagged correctly. It was just the light I shot onto the white background at 1.5 stops over to make the background pure white which seemed to be too much for the 135mm prime lens. Hard to believe since the background was 6-7 meters away from the camera.

Attached is one of the processed shots from the 24-105mm lens. If you compare to the shot below taken with the 135mm lens, which I fixed in Photoshop and posted earlier, I think you will probably agree the shot I am attaching here shot with the 24-105mm lens is still better in terms of color and contrast:

[Marc Schultz]

I just shot this with the 135mm lens at F/5.6. So I am happy to say there is no physical problem with the 135mm lens itself.

[Adzz]

Do think it could have been a glitch from the camera body? Shutter getting to many miles on it?
Its a strange thing? Perhaps an intermittent problem that a restart of the camera body put right?

PS: Like the Chilly shot.. nice
Adam