H6D-100c and the HCD lenses

It has now been a little more than a month since I received my new Hasselblad H6D-100c and I have got to test it out properly, at least in the field. One of the things I was most curious about was how my lenses performed on this new, physically larger sensor.

Most H-system lenses (denoted HC) were designed for full frame medium-format which corresponds to medium format 120 film. Often called 645, referring to the full size of the film of 6×4.5 cm, the true image area of the film most often is around 42x55mm. Thus, the HC-lenses image circle covers this area and are designed to be sharp in the edges and don’t make too much vignetting even on a sensor this size. However, more recent H-series lenses were made to work optimally for a slightly smaller sensor (37x49mm) that was widely used in the early days of digital medium format. These lenses, (denoted HCD), makes a slightly smaller image-circle than the HC-lenses and are the 24mm, 28mm and the 35-90 zoom. I own, and have grown to be very fond of, the hcd 28 and the hcd 35-90. Little has been known about how these HCD-lenses performed on the new full-frame sensor, and concerns have been raised regarding both sharpness and vignetting.

So, I have now tested my new full-frame H6D-100c with the HCD 28 and the HCD35-90. Basically I am happy with the results. The short message is that the there is no real cut-off of the corners. The vignetting is pretty significant, but easily corrected in both Phocus and Lightroom. Sharpness is good but not excellent in extreme corners, but very good in corners. As a landscape-photographer, the sharpness and vignetting does not represent any problem at all in most real-life situations as long as software profile-correction is used. However, this is just my opinion. You can have a look at the images below and judge for yourself.

All images are taken from a tripod, mirror lock-up, manual focus in live-view. Iso 64. Daylight temperature. Aperture as denoted and shutter-times from approximately 0.5-2 sec. Images are processed in Lightroom, raw-conversion only, no raw-sharpening, no other corrections. Standard lightroom lens-profile correction  where this is noted. Images are not cropped and are all 11600×8700 pixels. Exported as 3000×3000 max quality jpgs with medium output-sharpening for screen. The lightsource is a huge window with slightly overcast daylight from the left. I wish I could have found a scene more evenly lit by daylight, but that is not very easy in Norway this time of year…

1.Vignetting

28-f-4-uncorr

HCD 28, f4. Uncorrected. Rather heavy vignetting fully open, but no real cut-off of corners.

 

28-f-4-corr

HCD 28 f4, profile corrected in Lightroom. Vignetting is well handeled.

28-f-8-uncorr

HCD 28, f8. Uncorrected. Much less vignetting compared to uncorrected f4.

28-f-4-corr

HCD 28 f8. Profile corrected in Lightroom with an excellent result.

35-f-4-uncorr

HCD 35-90 @35mm, f 4. Wide open, there is rather heavy vignetting on the zoom without correction.

35-f-4-corr

HCD 35-90 @35mm f4. Same image as above but with Lighrooms profile correction yields almost no trace of vignetting.

35-f8-uncorr

HCD 35-90 @ 35mm f8. Uncorrected

35-f8-corr

HCD 35-90 @35mm f8, profile corrected in Lightroom.

35mm-f8-uncorr

To compare to my HCD zoom, I took this image with my HC 35mm @f8. Uncorrected. Less vignetting compared to the zoom uncorrected, two images up.

35mm-f8-corr

HC 35 @ f8, corrected.

 

2. Sharpness

28f8-100

HCD 28 @f8. 100% crop from extreme upper left corner. Notice how small this area really is by comparing to the two first images. 100mpx is really quite stunning. Profile-corrected but no raw-sharpening was employed.

35f8-100

HCD 35-90 @ 35mm f8. 100% crop of extreme upper left corner. Profile-corrected but no raw-sharpening. Sharpness is compromised in the very extreme corner. As I knew my zoom had a slight issue in the upper left corner used at 35 mm f4-f8 on close distance i made another 100% crop a little bit more centrally in the left corner, see next image.

35mmf8-100-2

HCD 35-90 @ 35mm f8. More central left corner. Profile-corrected but no raw-sharpening.

35mmf8-100

HCD 35-90 @ 35mm f 8. Extreme upper right corner is sharper than extreme upper left at this aperture, but still not perfect.

35mmf8-100

HC 35mm @ f8. 100% crop of extreme upper left corner using my HC-35mm lens to compare it with the zoom @35mm (see two images up). Sharpness is significantly better in extreme corners with this lens compared to the zoom.

50mmf8-100

HCD 35-90 @50mm f8. Extreme upper left corner is better @50mm compared to 35mm on this lens.

To summarize, I would say that vignetting is not a significant problem as long as you use profile correction. I have tried out both Phocus and Lightroom. Phocus does a slightly better job, with a little bit more evened-out result after my taste, but nothing that will make me change my standard workflow from Ligthroom. The only concern is on severly underexposed images (more than 2-3 stops) at iso 1600 and upwards, where I have found that the vignette correction may give some slight color noise (not shown here). This is not unexpected at all, but should be known when shooting with these lenses on very high iso. Regarding sharpness, I am happy with the HCD 28, at least from f8 and upwards where I usually shoot (f 11 – 16 is my go-to aperture on these lenses). The sharpness in extreme corners using the HCD 35-90 @35 is somewhat compromised at f8. It is better at longer focal lenghts and good in the not-so-very extreme corners. I know my lens has a slight issue from f8 and wider on close distance of the upper left, but this is very rarely a concern as I mostly shoot landscapes on longer distances and wider apertures.

I have also done some testing using filters, both a regular UV-filter that I use for my Lee 100mm push-on holder and a slim polarizer from Nisi. I will try to process and post these images sometime during next week.

Hope you found this helpful. Let me know if there are any specific tests you want me to do, and I will try to make room for it within a week or two.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s