ALPA of Switzerland - Manufacturers of remarkable cameras
Dec 18, 2005

New Leaf Aptus 75

1. Preface

This is a short user report of an initial test run with the new Leaf Aptus 75 used on the ALPA system. The digital back was a production series model, adapted for Mamiya 645 AFD/AFD II and set to large-format mode for use with the ALPA with X-sync. Pictures were taken uncompressed, for later use with the Adobe Camera Raw, on CF cards. Conversion was done with Leaf Capture 8.4 and 10 Pre-Release (Build 051122). We thank Graphicart of Berne, the official Leaf distributor in Switzerland, for making their test back available to us so early.

ALPA of Switzerland and the author are completely independent of the manufacturer and the distributors of the product tested. The fact that many ALPA dealers world-wide are also representatives for Leaf products has not been allowed to influence the results in any way whatsoever.

The sensors used in the Leaf digital backs (made by DALSA) have proven their ability for use with very wide angle lenses and de-centred positions of optical systems.

The author owns a Leaf Aptus 22 himself. ALPA as well as the author currently use the Aptus 22 as reference back.

2. Handling

The Aptus 75 has the same outer appearance as the earlier Aptus 22 and 17 with their large colour display at the rear. The sensor size is 36*48 mm, as with the Aptus 22. The new system also uses the same rechargeable batteries as the other models. The test took place at winter temperatures (0 to 10 degrees Celsius) so that any statement on power consumption cannot be definitive. Moreover, the energy saving features might still be improved further.

A 2 gigabyte CF card allows 27 pictures in uncompressed mode (45 with the Aptus 22) to be taken. The raw data file size amounts to some 64 to 68 megabyte uncompressed (approx. 42 to 44 megabyte with the Aptus 22). In compressed mode the number of possible pictures is doubled. The capacity depends heavily on the storage type and mode used (compressed/uncompressed, CF card, tethered with computer or digital magazine). It is comparable with that of the models Aptus 22 and 17 but the larger amount of data takes its toll. Developed as a 16 bit TIF, a file weighs 190 megabyte. Overall, the handling was easy, quick, stable and error-free at all times.

Navigation by menu has been improved in this latest upgrade. It features multilingual support and optimized positioning of the most important commands – there is no more scrolling for formatting the CF card or changing the ISO. Long file names are possible now and the software does no longer refuse to change the file prefix and change of ISO in one step. The only remaining criticism is that the menu guidance with the back in vertical position does not adapt its orientation. Digital and film backs can be attached horizontally and vertically on the ALPA regardless of format or manufacturer. The histogram adapts its orientation, so why not the rest?

Incidentally, the most recent software upgrade changes the menu in the same way for Aptus 22 and 17 with ISO 400 also becoming available shortly. The promised ISO 800 with the Aptus 75 are available from the beginning. The sensor itself is obviously a newer model. Basic ISO speed is 50 now.

3. Picture Results

3.1. Test criteria

Because testing time was limited, we have concentrated on the following criteria:

1. general picture quality with ALPA and Schneider lenses, especially with wide angle lenses
2. shift behaviour of the new backs/sensors
3. long-time exposure behaviour of the new backs/sensors.

Pictures and comparisons are available (sharpened/post processed in Photoshop, as well as untreated) for the three aspects investigated.

Leaf MOS files can also be opened in Camera Raw of Adobe Photoshop (only uncompressed at the moment) but raw conversion took place in Leaf Capture for the higher precision and quality of the output.

3.2. General Picture Quality (1)

Test pattern were made with an ALPA 12 SWA and the wide-angle Schneider Apo Digitar 5.6/24 mm XL, 5.6/35 mm XL and 5.6/47 mm XL.

The results of the combination ALPA/Schneider/Aptus 75 were simply astonishing. Whether the additional megapixels - and thus larger files - are needed depends on application and personal preference. For some, the still available Aptus 22 and even 17 would be more than sufficient. The Aptus 65 (28 to 29 megapixels, sensor roughly 33*44 mm) should become available in Spring 2006. On the other hand, Aptus 75 with its ample file size offers room for cropping or for easing – at least – the awkward staircases in architectural photography.

The new sensor exhibits pixel sizes of 7.2 micron. The limiting resolution is therefore 70 line pairs per millimeter/140 lines per millimeter. The Aptus 22/17 with their 9 microns are set to 55,5 lpm/111 lines - no problem for the high-resolution Schneider lenses and the ALPA system. Lenses designed for film resolution of 20 to 40 lpm still have to prove their ability to cope with such small pixels.

Caution: The 16-bit Dalsa sensor delivers extremely differentiated colour results. It is sometimes puzzling to see how the various light sources appear through the eye of such a sensitive device.

3.3. Shift/Movements (2)

The Apo-Digitar 5.6/35 mm XL was used with up to 20 mm shift (limitation of the image circle) and 47 mm XL up to 25 mm (maximum shift of the ALPA). No visible color shift and still very good sharpness in extreme positions (the shift movements equal to 55 up to 70 % of the sensor!).

3.4 Long-time Exposures (3)

Day and night shots were performed over the entire ISO range of 50 to 800 ISO. Digital differs from film in many ways. The picture quality in digital is much more dependent on the total light intensity available. It is therefore obvious that results at ISO 800 must differ between night and day situations. Incidentally, the Aptus 75 delivers full size pictures at ISO 800 where competitors bind their pixels and get reduced picture sizes. The image structure and appearance depends on personal taste - some users prefer clinical smoothness, others do not. As regards noise and details, the results range from outstanding to useful and correlate to the increasing ISO speed. The night shot at ISO 50 and some 16 seconds might speak for itself. A special de-noise software filter for the ISO 800 is promised. The only point of criticism is a possible banding/blooming in extreme light/dark parts at high ISO (see example). Let us hope that future software upgrades can eliminate such unwelcome effects.

4. Conclusion

The Leaf Aptus 75 is an inspiring piece of technology – quite possibly at the edge of what is possible today. The image quality with appropriate optics/camera is astonishing. The increased storage and performance requirements will make the hardware manufacturers very happy. The combination with the ALPA 12 SWA, WA or TC and Schneider optics gives you a high-end solution:

* extremely compact
* lightweight
* easy to use
* very stable.

Some points of criticism remain at the current stage but it should be possible to overcome them:

* menu not following the back orientation
* possible banding/blooming in extreme situations
* noise optimization at high ISO.

Faster read-out performance and optimized energy management are always on the wish list. And please, Adobe, give us the full pixel size from your Camera Raw. There are still 8*8 pixels missing!

Leaf offers various upgrade paths to the new backs. The author will upgrade from Aptus 22 to Aptus 75, which becomes the new reference back afterwards.


ALPA offers a complete high precision system for film and digital based photography. For digital use various adjustable (+/- 3/10 mm) adapters for Hasselblad H1/H2, Hasselblad V, Mamiya 645 AFD/AFD II and Contax 645 AF are available. All digital backs featuring a large format mode with X-sync capability can get used unrestrained. The ALPA system 12 offers a full range of digital lenses from 24 mm (over 100 degrees) upwards.

pdfReview Leaf Aptus 75
ALPA_LeafAptus75.pdf / 2.3 MB

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