Hasselblad 120mm f5.6 C T* s-planar and lens flare

[cg]

I just got a new old 120mm s-planar T* lens. I based my decision to

get a rather old lens on comments by photo.net members. I had rented

the 120mm f4 CF makro-planar and I was amazed at how much it suffered

from flare in backlit situations. This was the only lens I could rent

so I cannot say if I got a very poor sample. Other users have stated

that you must be careful to test many samples so that you get a good

one before purchasing. Since I was in the market for a used lens I

did not have the luxury of testing many samples of the CF lens.

However, others have praised the 120mm 5.6 C version and some even

think that it is a better lens. Based on preliminary tests, I have to

say that this is indeed a superb lens. It is very sharp and it does

not suffer from the same flare as the CF version that I had rented.

This is also my first C type lens. I am very happy with its built

quality and compact size. It will take getting used to the coupled

shutter and f stop ring but I think that it is a very nice feature.

[cg]

My question: What is the exposure compensation for barrel extension when this lens is used in the close focus range?

[frank_bunnik]

I have the same (black) lens. In spite of the coating, I find the lens a bit more prone to flare compared to other hasselblad lenses. I therefore got myself a mint professional bay 50 shade, including the mounting ring for the 50 and 60mm lenses, the 120-150mm and the 250 masks in a box for about US$ 80,00. I reccommend you get the same shade because the normal one does not help very much. at least, that is my opinion.

 

The lens is indeed a wonderful performer. The portraits I shoot with it are very very detailed, even when using a grainy film like tri-x. In close ups, sometimes using an extension tube, this lens is again extremely good, razorsharp but use a good tripod and lock the mirror up, prior to making the exposure, also use a cable release to minimise vibration. At infinity objects far away look a bit soft though.

 

In answering your question: no compensation is needed when you focus this lens at it's closest setting. Only when you use extension tubes or the bellows is compensation needed.

 

Hope this helps a bit, Frank

[cg]

Thanks for the info Frank. I do have the proshade. I use it with a b50-b60 adapter so I don�t have to change the b60 mounting ring on my proshade. Right now I have CF and CB lenses. I find the 120mm 5.6 S-planar lens flares less than the CF makro-planar lens I rented in the same situation. Both lenses had the proshade attached and aimed at a subject in front of a bright window. The light was diffused but it was enough to cause flare in the CF lens. There was "aperture shaped" flare in the CF lens and only a slight loss of contrast with the s-planar. I must have rented a really poor example of the CF lens and have bought a really good s-planar. I am actually beginning to really appreciate the quality of the C lens. This lens is really much better built than my CF and CB lenses. The next lens I buy will most likely be a C lens.

 

Another question I have is with the focussing action of this lens. Is it normal for the focussing to be slightly lighter near the infinity position and slightly heavier towards the 3 ft mark? I also find the focussing heavier when the lens is pointed up. How important is it to use the 120mm-150mm shade mask? I don't have one for my proshade but does it really make a difference?

[q.g._de_bakker]

Chris, and Frank,

 

You *do* lose about 0.6 EV using the 120 mm lens at its close-focus limit!

 

You can use the usual formulae to calculate exposure compensation with this lens.

 

 

[1] Magnification = Extension / Focal lenght

 

[2] Aperture correction factor = 1 / (Magnification + 1)

 

[3] Shutterspeed correction factor = (Magnification + 1)^2

 

[4] Correction in EV (stops) = log(Shutterspeed correction factor) / log(2)

 

The 120 mm lens has about 28 mm barrel extension.

Using [1] will show that the magnification using all of that is 0.2333.

Using [3] will show the shutterspeed correction factor to be 1.5222.

Using [4] will show that this is equal to 0.605 EV (stops) loss of light.

[q.g._de_bakker]

Chris,

 

The two parts that make up the lens (the heavy front part holding the shutter and all the glass, and the light back part holding the lens mount and not very much more. There are more parts, but... ;-))are held together mainly by the thread of the focussing screw. When you focus closer, there are less threads engaging, and the center of gravity is moving forward. This means that the heavy front part is tending to tilt more, putting greater friction on the few threads left holding the two parts together.

 

When focussing pointing the thing upwards, thus trying to screw the heavier part upwards too, you're fighting gravity.

[cg]

Thanks QG! I knew there has to be compensation and my test film shows it. This is a really sharp lens for short distance work. It's pretty good at infinity too. Since I don't shoot landscapes and do mostly studio work I think I will be very happy with this lens. By the way, the focussing is getting smoother the more I use the lens. I guess it's been on the store shelf too long.

[jasonthompson]

Q.G. -

 

Thanks for posting those formulae.

 

- Jason

[frank_bunnik]

2 Weeks ago a friend of mine called and sayd he wanted a Hasselblad as well and if I could look out for any good deals. I think I got him an excellent deal when 2 days later I arranged for him to buy a Hasselblad EL/M chrome, a recharger, an A12, a new type focusing hood and an acute matte screen, all in excellent state for only 350 euro from a reliable seller. After that he borrowed my 120mm and Wildi's Hasselblad manual. I think I have the second or third edition.

 

If I am not mistaken, I can not check at this moment, it says in this book that at it's closest focusing distance, no compensation is needed for the 120mm. I never compensate when using it this way, only when I use my 32mm extension tube I compensate half a stop and my slides are always well exposed this way.

[q.g._de_bakker]

Frank,

 

You are mistaken. ;-)

Compensation is definitely needed. The nomograms published by Hasselblad/Wildi do show that too.

 

The 120 mm fully extended plus 32 mm tube needs over 1 stop of compensation. Maybe your metering is heavily biased if your slides don't show the half stop you're off. ;-)

 

All Zeiss/Hasselblad lenses longer than 100 mm do need a non trivial exposure compensation when used with full barrel extension, without (!) extra extension added.

[cg]

Frank, I bracketed my shots using Provia 100 and the shots that were +.5 EV were closer to normal. The shots that did not get compensation were too saturated because they were a bit underexposed. I noticed this too with B&W film. The uncompensated close-up shots are a bit muddy compared to the normal distance shots that were on the same roll. When I use my 21mm tube I always have to add at least +.75 EV to my incident meter readings with my Minolta IV. BTW, the exposure times were around 1/15 to 1/125 so reciprocity was not a factor.

[cg]

That's a great deal on the ELM kit. I also got a nice deal on my 120mm s-planar. I got it from a UK dealer for 425 GBP. The lens has a 6 month warranty and the shutter had been overhauled. Looking at the images that it has produced so far, it is definitely a keeper.

[fredrik_lund_n]

<p>I just got a good looking 120mm/5.6 S-Planar C T* and has so far just taken a few shots<br>

<a href="http://www.flickr.com/photos/androgynousectomorph/tags/120mm56splanarct/">http://www.flickr.com/photos/androgynousectomorph/tags/120mm56splanarct/</a></p>

<p>I'm curious to know if anyone out there knows which lens hood to use for this lens. I have the 100-250mm B60 lens hood but is there a 100-250mm B50 equivalent (I know there is a B50 150mm designated hood, but seems there wasn't a 120mm range designated hood). There is a B50 100-250mm aftermarket "copy" on ebay that looks way too short for the focal range...</p>

<p>Maybe this is my best bet<br>

<a href="http://www.bhphotovideo.com/c/product/800633840-USE/Hasselblad__B50_Lens_Hood_for.html">http://www.bhphotovideo.com/c/product/800633840-USE/Hasselblad__B50_Lens_Hood_for.html</a></p>

[q.g._de_bakker]

<p>The Bayonet 50 "150" hood is the correct one. <br />It was later marked "100 - 250", and the same as the one B&H is advertising (unless - no picture, so how do we tell? - they are selling the chinese copies).</p>

<p> </p>