richg101

If you read my post I said 'I have a feeling'. my feeling was wrong. Fair enough. well there you have it. sony could have made a smaller lens with performance to match the shite canon offering, but instead used that extra space for further elements. the result? a lens that delivers resolution good enough for the 42mpx a7rii.

I have a feeling the reason the sony is so large is that it might be a re-purposed lens. probably originally designed for a-mount, or at the very least designed to be onfigured to be used with a a-mount camera, and then the optical design has been translated into e-mount. the additional 30mm length to make up for the lack of mirror. yep. micro lenses, cover glass etc. all make shorter back focus distances a potential problem. The Loxia lenses take leica style designs and apply correction for micro lenses and cover glass.

a 80mm/2 designed for what looks like the sony 50mp cmos would be small and lightweight - no heavier than a 50mm/1.4 for full frame. The lack of mirror means the system benefits in the same way a leica M system benefits - small lenses due to not needing to be placed 45-75mm from the sensor to clear the mirror. think scaled up Loxia lenses. fast, compact, very high quality.

A MF to FF speed booster is not a viable product because of a few problems:- 1. a good quality optic will be very expensive. the Kipon unit won;t perform as well as the speed booster ultra, and as shown on my tests a few pages up, even the speed booster ultra negatively affects the overall image quality when compared to a straight lens on full frame. add to that the need for electronic contacts to use lenses like the contax645 or rolleiflex hy6 'digital ready' lenses. the cost will mean the customer base will be limited. 2. Most speed booster purchasers do so to get around having to pay for a full frame camera. Therefore they'll also be less likely to invest the huge amounts in MF glass that (assuming a focal reducer were optically clear) will actually be worth focal reducing. a 110mm/2 hasselblad, a schneider 180mm/2.8, a schneider 80/2, contax 80/2. 3. because the likelihood of the focal reducer being of good enough standard (ie, better than a sb ultra) being almost impossible, and the likelihood that hardly anyone will be able to acquire a desirable fast mf lens, the likelihood that an end result will exceed a fast full frame lens, let alone meet that of what is possible on medium format is slim. All said and done, I'll be buying a kipon mf to ff focal reducer, but in no way do I expect it to deliver the same quality I get from the same lens on MF.

the magic comes from the available optics for a given format. 1. you cannot buy a 60mm/1.4 aps-c lens equivalent to an old leica summicron 90/2 when used on full frame. yes you can stick a 0.7x focal reducer on there, and I have done so (with the sb ultra on a a7rii). the amount of defocus is the same but the rolloff is quicker on the focal reduced lens on aps-c. the in focus areas are also drastically inferior, and there is significant reduction in fov, and added distortion. all of these attributes contribute to the advantage of the larger sensor. 2. you cannot buy a 50mm/1.4 lens for full frame that is equivalent to an 80mm/2 when used on medium format wide open. close down 1 stop respectively and the real world advantage of medium format becomes even more pronounced. I really wish there was a full frame lens system capable of acheiving the same look from my mf camera since i'd no longer be limited to running 80iso. at the moment the limitation of slower lenses and 80iso means i am confined to flash work or daylight shooting. until yourself or someone else designs and manufactures a viable alternative for smaller sensors the professionals will continue to buy into the phase one system for remortgage worthy money!

Wrong.

I agree with this to a point. my 9year old leaf aptus ii 10 at 80iso (56mpx ccd, 16 bit) destroys my sony a7rii for colour in situations where there is good light. Still I think you are wrong to disregard the effects of a large sensor on dof rolloff. the new Phase 100mpx back is a sony cmos sensor. being 16bit and developed to mimmic the desired look you get from a ccd in its comfort zone has created the best mf sensor ever apparently. in good light I expect my ccd will deliver just as beautiful images, but in bad light the phase 100mpx cmos makes me wanna cry at how good it performs.

you need to burnish the casing back to gloss with a very fine polishing pad. i think a 4000 abralon pad will work well on this. leave the taking lens on for protection of the rear element and to use as a handle to hold onto, then rotate the iscorama in the abralon pad. make the abralon pad moist but ring it out so it's almost totally dry - just damp. a good quality black marker pen like a sharpie will darken the grooves on the grip. I'd avoid wax based products since these are nearly impossible to remove from glass if they end up on the elements. i would however maybe look at t-cut or even brasso as an option. as long as the cloth is almost totally dry and you quickly rub the casing uniformly the abrasiveness of t-cut may be the answer. try the locking buttons first to test the processes. then you don;t run the risk of ruining the main casing. ps. the parts that are still black are infact anodised aluminium so mask them off so you don;t polish away the blacking of the metal!

point of focus is the text on the front of the lens. bokeh bubbles are the same for both shots meaning the ratio between the in focus and fully out of focus areas is the same. HOWEVER, on the aps-c shot the canon text on the camera body, the underside of the tripod head, and the text on the flash are are more blurred than the full frame image. so for a bigger sensor the dof rolloff is slower and therefore more of the camera is in focus. as distance increases and focal length is lengthened this attribute is magnified.

i'm gonna have to start working hard to get some points. anything to make up for my 1.5" fully extended. this opinion is one of the main reasons certain very good photographers miss out on the better work - the disregarding of how important equipment really is from separating two equally good photographers. naturally the one who decides to go that little further - investing in equipment you need to pay a lease to use, rather than saying to themselves they can spend the extra money on a holiday or a new car and carry on using run of the mill canon crap. shooting medium format digital separates the men from the boys in the same way shooting Alexa and cooke s4 differenciates from someone shooting c300ii and eos lenses. they're not that far off, but the people with the ability to differentiate see the difference and value the difference. If it wasn;t there, phase one and arri wouldn;t be servicing the upper end of the market.

yes, this is true. but a speed booster is a focal reducer. the ultra is a marvelous piece of glass and as a rule a basic 50mm f2 + speed booster ultra (creating a 35mm/1.4) will vastly outperform most true 35mm/1.4's. Technically a sigma 35/1.4 will meet or exceed, but at the cost of losing all sense of soul and character.

Full frame https://c2.staticflickr.com/8/7697/27662722381_982d10fc99_o.jpg APS-C + SB Ultra https://c2.staticflickr.com/8/7272/27737331565_423e3503be_o.jpg now I'm gonna say that in order to view the differences you should download the full size files, and bring them into photoshop so you can flip from one layer to another. the differences wont be apparent without. The main thing is overall image quality. shorter focal lengths just don;t deliver the same refined in focus areas - the point of focus on the aps-c shot is drastically harmed by the purple fringing. Since the in focus area is less refined than the ratio between the in focus areas and the defocused area is greater- providing a greater level of 3d pop. . but look at the defocus. background looks about the same level of blur, but the blur level on the lens cap (circled) shows that the rolloff is different. it's slight, but the difference is there. this difference in rolloff is as far as I am aware dictated by circle of confusion of the different formats. Lets assume we replaced the lens in shot with a human face, more of the face will be in focus with the full frame sensor area - due to the rolloff. from the tip of the nose to the ears, the overall perceived rendering will show the entire overall face to be more in focus than with a wider lens. the overall background blur will be the same, but the distances close to the point of focus will have a deeper useable dof. The point I'm making is that physics and available lenses give larger sensors the edge.