New 35-100mm f2.8 and ND filters

I've been getting used to this lens, finding that my years of relying on the 14-140mm has made me very lazy, both in how I think and how I shoot. It is quite a shock.

The weather in the UK has been exceptional for February, with bright warm sunshine, so I carried out a series of shots to see how to use the lens wide open (for minimal DoF) with a lot of light.

First I applied the setting I'd been reading about on recent DPR posts: leave the aperture fixed at f2.8 and set the ISO to Intelligent ISO, to let it dictate the shutter speeds. This is new to me and it worked very well, in one instance forcing the shutter speed up as high as 1/8000 while the ISO stayed at 200. The results are pleasing when Photoshop applied the Auto correction: sharp, well exposed and with good colour.

Then I used the Tiffen ND filters, gradually adding one at a time to build up to a 5-stop reduction in light intensity and correcting for under-exposure using the same Auto correction in Photoshop. These results are not as pleasing: a much cooler colour, more residual highlights or over-exposed areas, and not so sharp.

My conclusion is that I shouldn't bother about filters unless I really need to slow down motion e.g. for waterfalls. Which I haven't yet tried, being a bit short of waterfalls. Do you have any advice about getting better results while adding ND filters?

Cameras used were the GX80 and GX7. Although the examples show slight differences in distance from the flowers, the different result is typical across the range of shots I took.

Thanks - Maggie

Using ND 1.8

No filter

"gradually adding one at a time to build up to a 5-stop"
You know that all that makes for less sharpness because of more and more glass surfaces right? Any color cast will be pronounced too!

maggiemole wrote:

I've been getting used to this lens, finding that my years of relying on the 14-140mm has made me very lazy, both in how I think and how I shoot. It is quite a shock.

The weather in the UK has been exceptional for February, with bright warm sunshine, so I carried out a series of shots to see how to use the lens wide open (for minimal DoF) with a lot of light.

First I applied the setting I'd been reading about on recent DPR posts: leave the aperture fixed at f2.8 and set the ISO to Intelligent ISO, to let it dictate the shutter speeds. This is new to me and it worked very well, in one instance forcing the shutter speed up as high as 1/8000 while the ISO stayed at 200. The results are pleasing when Photoshop applied the Auto correction: sharp, well exposed and with good colour.

Then I used the Tiffen ND filters, gradually adding one at a time to build up to a 5-stop reduction in light intensity and correcting for under-exposure using the same Auto correction in Photoshop. These results are not as pleasing: a much cooler colour, more residual highlights or over-exposed areas, and not so sharp.

My conclusion is that I shouldn't bother about filters unless I really need to slow down motion e.g. for waterfalls. Which I haven't yet tried, being a bit short of waterfalls. Do you have any advice about getting better results while adding ND filters?

Cameras used were the GX80 and GX7. Although the examples show slight differences in distance from the flowers, the different result is typical across the range of shots I took.

Thanks - Maggie

To be honest there is something going even with the non ND shot. I don’t know if it’s jpg artifacts from the forum or your post processing but the non nd shot should be much cleaner at those settings.

epozar wrote:

"gradually adding one at a time to build up to a 5-stop"
You know that all that makes for less sharpness because of more and more glass surfaces right? Any color cast will be pronounced too!

I hadn't appreciated that adding more glass would reduce sharpness (duh!!) - so thank you for that! Tiffen kind of encourage stacking with their screw system, though I should have thought about it.

The ones I have are meant to have zero colour cast and it's difficult to detect any by visual inspection. But the stacking effect will certainly increase any colour cast, as you say. Back to the laboratory ....

JLWPhoto wrote:

To be honest there is something going even with the non ND shot. I don’t know if it’s jpg artifacts from the forum or your post processing but the non nd shot should be much cleaner at those settings.

Here's the extract from the RAW file of the "no filter" image earlier. In processing, I used only the Auto setting in Camera Raw and then sharpened a bit with the High Pass filter in Photoshop. It didn't seem to be very much at all.

RAW, unprocessed

If you think this is still unexpectedly poor  (and feel free to process the Original Size version) please let me know - it may be my processing choices.

Thanks a lot

Maggie

Skeeterbytes wrote:

maggiemole wrote:

The ones I have are meant to have zero colour cast and it's difficult to detect any by visual inspection. But the stacking effect will certainly increase any colour cast, as you say. Back to the laboratory ....

Best practice would be to set white balance when adding the filter and of course, shooting RAW. While you're dialing in, perhaps shoot a gray card or color chart then using the color correction eyedropper tool when processing. You could then create a custom profile for the filter.

Happy experimenting!

Rick

That's a good thought, a custom WB profile for the filter. I've only done that in infrared before. Thanks for the suggestion. I do shoot RAW as a matter of course, and the samples I posted came from RAW files, so there shouldn't have been any JPG artefacts from the camera.

Maggie

Tom Axford wrote:

maggiemole wrote:

No filter

This shot has much more noise than I would expect for a correctly exposed shot at ISO 200. Is is sooc or have you processed it yourself? If so, how?

Not sooc, Tom. Processed from RAW by using Auto in Camera Raw which changed settings to Exposure +0.88: Contrast -22: Highlights -72: Shadows +73: Whites +26: Blacks -8: Vibrance +12: Saturation +3. Here's the original RAW before these changes:

RAW file crop

Looking at what I've just typed out, that's possibly a lot more processing than I'd thought Auto would apply. I'll try to check what just Exposure changes would do. Then I topped off using the High Pass filter in Photoshop, set to 1.8 if memory serves.

Maggie

PS This is just using Exposure +.90:

Exp +.90 only

I think there is less noise, but the background stays dark ... too dark? No sharpening. Thanks for your help!

Maggie

Could you share a bit more what that Intelligent ISO does compared to the plain Auto ISO?

Mark9473 wrote:

Could you share a bit more what that Intelligent ISO does compared to the plain Auto ISO?

I'm not the person to explain this properly, Mark, and I hope someone else jumps in! My interest was caught by a discussion (title forgotten)  pointing out that changing ISO does not change exposure, i.e. the amount of light captured, only the sensor's response to that amount of light. Since my habit had been to shoot aperture priority and fix the ISO I was often getting too high a shutter speed to capture just enough light. It just made sense to me to fix both aperture and shutter speed dependent on the DoF I aimed for and recognising the shutter speed needed, and let the camera handle the consequences via ISO. In general, it keeps my ISO lower than Auto ISO does, and I'm hoping that it therefore reduces noise.

Intelligent ISO detects movement - or the lack of it - in the subject and decides that if there is little or no movement it does not need to use a fast shutter speed and so keeps ISO low. Auto ISO simply reacts to brightness and I think it allows for both a varying ISO and a varying shutter speed, which is not likely to be optimum.

I hope I'm right and I hope someone else can add a better explanation.

Maggie

maggiemole wrote:

Mark9473 wrote:

Could you share a bit more what that Intelligent ISO does compared to the plain Auto ISO?

my habit had been to shoot aperture priority and fix the ISO

I have my cameras on auto-ISO, limit 6400.

In general, it keeps my ISO lower than Auto ISO does, and I'm hoping that it therefore reduces noise.

That would be very interesting. I don't quite like why Panasonic first adjusts ISO before aperture.

Intelligent ISO detects movement - or the lack of it - in the subject and decides that if there is little or no movement it does not need to use a fast shutter speed and so keeps ISO low. Auto ISO simply reacts to brightness and I think it allows for both a varying ISO and a varying shutter speed, which is not likely to be optimum.

I hope I'm right and I hope someone else can add a better explanation.

Maggie

Thanks! I'll have to play with it a little bit I guess.