Apo-Ronar and filter?

[allsystemsfail]

I have an Rodenstock apo-ronar 360 in a copal 3. I have shoot a few sheets with it and have never been thrilled with the sharpness. When focusing it, it seems to really snap in to focus, but when I loupe the negs thier not quite sharp. So the other day I shot a scene two ways. One with no filter and one with an orange filter. I shot them back to back without changing anything and the one with the orange filter is noticeably sharper. I've read about using an orange filter with convertible lenses and was wondering if this lens is helped by doing the same. Although I thought the Apo was designed to correct that. Any thoughts?

 

[epatsellis]

did you check focus after stopping down? Your lens may suffer from mild focus shift.


erie

 

[keithwms]

Is this a process lens?

 

[Tom Hoskinson]

did you check focus after stopping down? Your lens may suffer from mild focus shift.


erie

No focus shift with my Apo-Ronars (150mm, 300mm and 450mm). All three of mine are Tack Sharp lenses. I use the 150mm as a macro lens (mounted on a Bellows) on my 6x6 SLR (with both black and white and color film - and I rarely use filters). The Apo Ronars are diffraction limited process (copy) lenses that also work quite well at infinity.

 

[Dan Fromm]

I"m with Tom. My 150 Apo Ronar is just fine on 2x3 at all distances.

Allsystemsfail, I suspect your lens has a problem. Are you sure that the cells are fully seated in the shutter? If your camera has wooden boards, its possible that the board may prevent the rear cell from going all the way into the back of the shutter.

Erie, process lenses were made to be focused by tape measure, don't shift focus on stopping down.

 

[keithwms]

My 600/9 apo ronar has no focus shift from near-UV to near-IR, it's wonderful. And it's a process lens.

My thought, regarding the proces lens question, wasn't with regard to focus at infinity. As far as I have seen, the issue is simply that these lenses give best flat-field performance at 1:1 or so.

The reason why I asked if this is a process lens is that these lenses may have higher than normal UV transmittance, by design. That being the case, in a landscape photo, you might start to see atmospheric scattering on some films, which see quite far down into the UV. This might contribute to an unsharp appearance. Remember that Rayleigh scatter goes as 1/(wavelength)^4 so it can be an extreme effect in a landscape shot.

That's the only reason I can cook up, for now, why a red filter might have gven a sharper negative.

If you'd show us the negs then we might be able to say more.

 

[allsystemsfail]

Thanks for the replies guys. I wondering if it could be sloppy shooting. I was shooting another test this weekend And I was paying close attention to when I fired the cable release and noticed some movement. I was using a short (8 inches) and stiff cable release and I think when I push it in it pushes on the lens a little and causes some slight shake. So I switched that one out for a longer much more flexable one and did another shot and did not notice any movement. I processed the film this morning and guess what? One was sharp and one not so sharp. I should have learned by now, It's usuailly user error and to stop blaming the equipment.

Rich

 

[keithwms]

Okay, good, I didn't like my explanation except for sweeping landscapes on hazy summer days

 

[vet173]

Thanks for the replies guys. I wondering if it could be sloppy shooting. I was shooting another test this weekend And I was paying close attention to when I fired the cable release and noticed some movement. I was using a short (8 inches) and stiff cable release and I think when I push it in it pushes on the lens a little and causes some slight shake. So I switched that one out for a longer much more flexable one and did another shot and did not notice any movement. I processed the film this morning and guess what? One was sharp and one not so sharp. I should have learned by now, It's usuailly user error and to stop blaming the equipment.

Rich

Exactly the same experience I had. I now use a 24" release.