PhotoLab5 and Teleconverters

I was out plane spotting on Dec 7th and was using my rarely used Pentax HD DA 1.4 WR Teleconverter attached to my Pentax 55-300 PLM zoom lens. I got some great shots but when I got home and downloaded them to my computer and opened the the DNG files some of the files had the warning that there was no DXO optics module for this image. I could not use some of the features in PL5. Puzzling?? The Lens is reported correctly in Maker Notes but also ExtenderStatus is reported as Attached. I chalked the problem up to the ExtenderStatus field being reported as Attached. Oh well I have other processing programs. As I was scrolling through the almost 300 images I noticed some images did not show the “No DXO Optics Module” warning and that I could use all the features of PL5 for this particular and also other images as well. I found that the focal length reported by the camera with the lens zoomed back was 238 mm since I was tracking the aircraft in bound and as the aircraft got closer in to the camera I would zoom back to keep the aircraft in the frame the. Other images reported 420 mm and those were the ones with the “No DXO Optics Module” warning. Has anyone else experienced this problem?

Ok, My work around for my teleconverter problem with PhotoLab 5 is to use an old and no longer updated EXIF editor to change the focal length reported by the camera which is 420 mm for my Pentax Mk III using the HD DA 1.4 WR teleconverter and full zoom of 300 mm on the lens. I tried using EXIFTool but my coding skills are nill but it can be done using EXIFTool. I used PhotoMe to change the reported Lens Focal Length and I can process my images fully in PhotoLab 5. Its kind of unbelievable that I am again encountering problems using my favorite processing tool. But Hey, all is well for now.

I’m thinking of purchasing the 1.4 TC and would want to use it also with my 55-300 PLM. Heck, some times I would also be using it for aircraft, too, though I’m thinking more for birding.

I checked because I thought DxO listed TC’s in the compatibility list but I see nothing in the Pentax lens lists. I wonder if PhotoLab is looking at the metadata and saying that “420” cannot possibly be that lens so it refuses to believe the EXIF lens model?

I’m assuming with aircraft shots you’d be able to tell easily how the sharpness is? My theory is it’s processing the images as if the unaided lens were in use. So the distortion correction for your “238mm” shot will be as for the lens alone at that setting. Assuming the TC adds no further distortion (or little enough not to be noticeable) then that aspect should not be an issue. However, where I would be concerned is any softness measured on the unaided lens would be magnified and therefore not properly addressed by the module.

Usually it’s more about a certain degree of softness than distortion, as the TC makes use of the center part of the lens. More important that it works satisfying with the lens in question.

[ Myself, I sometimes use an AF-S TC-14 E II from Nikon and I’m happy to fit it with f4/300mm or f4/70-200mm (losing 1f-stop + 1f-stop to step down). ]

I’m tending towards not buying it at this stage. No proper support from PhotoLab, and some users report what Pentax do claim… that it can sometimes miss focus with this lens.

I admit I was only super tempted now because it has reduced significantly in price. Maybe I will leave it and see if it goes any lower, as the trend suggests.

Yes, I was very happy when → these combinations were supported as I took some really long range shots in the dawn & from a tripod and any little sharpness improvement helps. :slight_smile:

While I can handhold my lightweight 300mm (the lens’ vibration reduction works very well and stabilizes the visible pic, keeping the subject ‘in the frame’), it’s getting more difficult for me from 400mm onwards.

I own the same lens, but not the TC 1.4. Probably the combination is not supported or not recognized.
The lens is recognized, but the TC possibly not, inspite of the Maker Notes.
If the EXIF reports a focal length >300mm and PL5 isn’t aware of the TC, there is a contradiction between the focal length and the 55-300mm lens. That’s the cause of your “not supported” message. You changed the focal length in the EXIF to something <300mm and your error disappears. This means, that the correction that is applied is the one for the 55-300mm lens without the TC.
The result wil be better (optical corrections and lens sharpness for the 55-300 applied) than without your hack, but probably a bit less than with the correct profile for lens+TC.

I don’t agree completely. The TC uses not only the center part of the lens, otherwise the maximum aperture would be reduced with more than one stop (TC1.4) or two aperture stops (TC2). The change in aperture when using the TC is a straightforward result of the fact that your aperture is calculated as f/D, D being the diameter of the lens (taking the effect of the stop in consideration) and f the focal length. So if you attach a TC1.4, the focal length is increased by a factor 1.4 and your aperture number as well. So one aperture stop. An aperture of e.g. 4 becomes 5.6 with the TC1.4 and so on.
A TC magnifies all lens errors. Also distortion. For the best possible optical corrections, we would need a PL lens module for the lens+TC combination. A TC can introduce new errors as well, as it is an additional optical component.

Well, with zoom lenses it’s not so easy.

I have been using the Pentax 55-300 PLM and the Pentax 1.4 TC combination for slightly over a months now and have not noticed much softness with the combination when shooting with the Pentax K-3 Mk III. I think what little softness has been created by the photographer as I have been shooting at longer distances and sometimes with a setting that is not ideal, which creates the softness. For instance, shooting with the shake reduction not set to panning but to normal shake reduction mode when aircraft are in horizontal flight.

What tempted me and sold me on the TC was the photos I’ve seen on Pentax Forum with the 1.4 TC attached to a Pentax D-FA 150-450. Those were some impressive wildlife images. So that sold me on the TC and 55-300 PLM combo. My only complaint is that the TC kicks the aperture up to f/9.5 at full zoom which requires a lot of light or the ISO can get pretty high but on overcast days I still get acceptable images. when I develop the DNG files in photoLab after I edit the reported focal length with EXIFTool GUI.

I routinely shoot with the 55-300 PLM at f/8 because it’s a bit soft/abberant wider than that. When I had the earlier WR and ED versions, I routinely shot at f/11.

That includes aircraft in bright sun and birds in the forest. PhotoLab enables the latter with DeepPRIME.