Illustration of 35 summilux ASPH contrast variation

[runkel]

I think this pair of 35 summilux ASPH shots of the same subject, exposed

similarly in full sunlight, gives an interesting view of how much less contrast

the lens has wide open than it does stopped down. With this subject, I think

the shallow depth of field contributes to the lower-contrast look by muting the

busy foreground.<p>

 

I must prefer the second image.<br>

 

<center><a href="

title="Photo Sharing"><img

src="http://static.flickr.com/74/247203290_e81e553d24_o.jpg" width="650"

alt="Cascade Head2" /></a></center><center><i>Stopped down (f/11 or

so)</i></center><br><br>

<center><a href="

title="Photo Sharing"><img

src="http://static.flickr.com/95/247203278_bfaf21f1ba_o.jpg" width="650"

alt="Cascade Head1" /></a></center><center><i>f/1.4, 3-stop ND filter</i></center>

[jsbc]

how much of the "loss in contrast" in the 2nd photo is attributable to the ND filter?

[runkel]

My thought is not that much, as it is a modern coated B+W, 52mm, used with a step-up ring and the proper shade for a Nikon 35/1.4. I've used this setup before with fine results. I don't think the ND filter has a material effect other than cutting out 3 stops of light.

[michael_b._elmer]

The filter makes the comparison invalid. In my opinion your pictures clearly demonstrate why filters should never be used on Leica lenses. Here, the filter produces vignetting and reduces contrast and saturation.

[cabophoto]

Michael,

 

as I'm sure you know light fall-off towards the edgaes of the frame is more pronounced at wider apertures. This has nothing to with the use of a filter.

 

I have a B&W MRC UV filter on my 35/1.4 ASPH (almost) all of the time. It doesn't cause any vignetting.

 

Carsten

 

http://www.cabophoto.com/

[andy middleton]

With or without filter the 2nd image is far better to my eyes..The contrast on the first image

and lack of shadow detail (at least on my screen ) is extreme.

[runkel]

Michael,

 

I'm not sure I agree with your interpretation, although in thinking through the sunny-16 math just now (metered at 125), I realize the second image couldn't have been exposed at f/1.4 as I seemed to recall, but must have been more like f/4 or even f/5.6, which does tend to undermine my original thesis. So, mea culpa there.

 

To me, however, this only deepens the interest of the comparison. I think if a single high-quality filter changed (I don't say "degraded" in this case because I prefer the second image) image quality to the extent you suggest, and so visibly even on a little computer screen, we would not see the endless debates in online forums about the wisdom of using "protective" filters. This is a single layer of glass from the same maker most often mentioned when recommendations for the best "protective" filter are sought. The ND property reduces light transmittance, but I would not expect it to change the quality of the image any more or less than a simple UV filter from the same factory. I make these observations as an avid member of the "no protective filters" camp.

 

I don't think the image shows any mechanical vignetting, although I suppose that is possible. The normal illumination fall-off for this lens at f/5.6 is still about a stop (vs. 2.5 stops wide open). I think the darker upper right corner is just a function of the sun's position.

 

I will be interested to hear other opinions about whether the ND filter may account for some or much of the difference between these two images.

[neil_grant]

Matthew, I suggest you do a controlled experiment. Take test photos with and w/o ND filter.

Achieve correct exposure using the shutter. (ie work at a constant aperture). Then compare.

[christopher_a._junker1]

With reference to neutral density filters, is there such a thing as a variable density filter that compensates for vignetting on wide angle lenses? As to the controlled experiment, reduce or eliminate camera shake by use of a table top or regular tripod and a cable release or use of the self timer release. As with the others, my preference is the f1.4 shot. Look forward to your next effort.

[runkel]

Christopher,

 

Such variable-density "center filters" do exist for large-format lenses; each modern lens model that could benefit from a center filter has a corresponding (and expensive) filter computed to match the lens's particular properties. Using such a filter reduces the effective aperture of the lens by several stops, which I assume is why they do not exist, to my knowledge, for 35mm-format lenses, which are designed to be usable at all apertures. It would defeat most normal purposes for a fast 35mm lens to shoot it wide open with light-robbing filter attached. Also, most wides for 35mm, including modern Leicas, are at least somewhat retrofocus, which moderates fall-off.

 

I'll have to try a little test the next time I'm ready to finish off a roll of slide film. It will be mostly an academic exercise, of course, because if you want to shoot during the day at wide apertures, an ND filter is usually the only option.

[christopher_a._junker1]

Matt, thanks for yuor response. I'd forgotten about the variable density filters for large format and the movie industry. Using f1.4 in broad daylight without a ND filter would probably mean film rated at ASA 100 or lower.