why my CT* 80mm is not as sharp as my 35mm (cheaper) lens

[toby_chey1]

Hi,

 

<p>

 

I bought a hassy 500 c/m together with this lens and a a-12 magazine

used

I shot a roll of e100s on detailed buildings

i checked the transparency with a Zeiss loupe at 9x

The result dissapoints me.

With the same magnification, slides from my nikon (28mm f2.8 ais lens on

same film) is sharper and more contrasty than my slides form hasssy. Why?

Does the slight unstabe fitting of magazine wll result in this problem?

a lens hood sure will improve contrast right? but does it increase

sharpness? how about a skylight filter? (my hassy has no lens hood nor

filter.

If the problem is from y lens, then i will refund my money (i spend

$1800 cdn on it. the camera looks fine, and the lens looks fine, but the

magazine is showing long time of HARD use.

 

<p>

 

--

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Toby Chey @ tchey@ibm.net

Photography, Architectural and Industrial Design

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[james_d._steele]

The back could certainly be the problem. There shouldn't be any play in it. Also, check to see if the serial number on the insert matches the serial number on the back itself (i.e the last 3 digits, I think.). If it doesn't you may have a problem there also. They are matched and should not be interchanged.

[frank_sheeran__remove_2nd_1664873968]

Hi Toby, <p>

 

It sounds like you were comparing apples to oranges, when you

<i>really</i> want to try to compare apples to... bigger apples 8-)

I see about 5 problems... <p>

 

1. Lens hoods are critical, even more so when lenses pick up natural

amounts of dirt and dust. Don't just worry about the sun - the entire

sky, ceilings, any other brightness that can "see" the front element of

your lens will lower contrast. A hood minimizes that. <p>

 

2. Lenses that cover wider film can't really push more total detail

through; they merely spread out about the same amount of detail

over a larger area. The "only" advantage of MF is that you enlarge

2x-6x less for the same result, so <i>grain</i> is 2x-6x smaller. So,

it is quite natural to see less detail per film mm on larger formats. Your

comparison using a 9x loupe on both is thus not realistic. You'd want

to use a 9x loupe on 35mm and say, a 4x loupe on MF, and see

which gives better results. <p>

 

3. Which isn't good enough; 9x on 35mm is like a 8x12"

print, at which point E100 grain is hardly visible anyway! Better to

get a PhotoCD-Pro scan of each, at 6000x4000 - you can actually

see alot of grain on Velvia 35mm at that resolution, and more

topically, ALMOST NONE on MF... Of course format shapes differ,

but you want to get say, 1/8" on the building surface = 1 pixel,

(for a 60 foot tall item) in <i>both</i> scans. <p>

 

4. And you want to compare identical compositions. If its a building

facade or some other flat surface where only magnification matters,

you can frame your shot with any lens. If its a 3-D scene, you'll want

to compare that 80mm Hassie to a $80 50mm/1.8 on the 35mm, to

keep the angle of view about the same. Also, the cheapest Nikon

50mm will probably be alot better than your 28mm/2.8, especially in

the corners. <p>

 

5. if these were exterior shots, you were about 2x farther

from your subject with the 80mm MF than the 28mm 35mm. You

could expect more haze or bus exhaust cutting contrast. Is that a

factor? <p>

 

In summary: it is natural that your comparison of like-magnification

showed much less sharpness on MF, and that the hoodless Zeiss

had alot less contrast than your hooded Nikkor. Use the d*** hood,

and this time compare <i>grain</i> across the entire scene as well

as double-checking that for any given detail (window, doorknob,

etc.), <i>not</i> per film mm, that the MF image is at least as sharp as

the 35mm. <p>

 

And finally, if grain, 2x3 format, and prism viewfinding aren't

problems with your current work, stick with 35mm. If sharpness of

your 28mm is a problem then an MF SLR wide-angle won't be any

sharper; you'll want to either move to rangefinders (Leica M4/M6,

Contax G1/G2, Fuji 645/690, Mamiya 6/7) or normal-angle lenses

(50mm for 35mm, 75, 80, 100 depending on MF format). <p>

 

Frank

[chun_in_martinez]

I personally think that the following might the most common causes of unsharp pictures in this case:

 

<p>

 

1. No mirror prerelease used.

2. Shaky tripod.

3. Back alignment.

4. And personally think that the suspicious cause here is that the film was inserted backward and caused out of focus film plane.

[andreas_carl]

To Chun: How can you posibly insert 120 film backwards in a Hassie? It's physically impossible. I recommend the following: A) Compare lenses of same view angle, i.e. Hassie 80 mm with Nikon 50 mm lens. Then have prints made the same size (11x14 or 16x20 or what you think you would use most). In the unlikely case that you don't see a difference, return your Hassie.

[p._aing]

Without more details, I agree that it's likely techniques as Chun In Martinez said. The theoretical argument of "larger format=less resolution on the film" doesn't seem to hold here. f=28mm for 35mm format is wide angle. f=80mm for 6x6 is about normal angle. Roughly speaking, a 80mm lens for 6x6 may not be as difficult to design and manufacture as a 28mm lens for 35mm. Without any real figures, it is a quite evasive discussion. But aren't lens for Hasselblad supposedly made almost regardless of price/value consideration, I mean low compromise in manufacturing tolerance...?

[mark_hubbard]

Toby, I vote for getting your money back if you can. Although I don't know the AIS version, the AF (newer) version of the Nikon 28 f2.8 is in my experience one of the WORST lenses that Nikon makes. I use mine only for completely non-critical snapshots and nothing else. If you're getting even less clarity from your Hasselblad, it has a serious problem. Better to dump it and start over if you can. You should be thrilled, not disappointed, with what you see. When I look at chromes shot at infinity with my M7, I can distinguish detail and crispness corner to corner that cannot be seen in person with the unaided eye, such as phone numbers on small signs a quarter mile away. I even get those results with my older C330 equipment. Don't settle for less! The Hassy should blow you away. Mark

[frank_sheeran__remove_2nd_1664873968]

Hi Mark, <p>

 

I shoot primes on 35mm on tripods with MLU. With Toby's mentioned

E100, a shot from a Canon EF 50mm f/1.4 will also render detail unseen

with the naked eye - even invisible under a 4x loupe. When a PhotoCD

Pro scan is viewed at 100% (my screen's 100dpi so it's equivalent to a

5'x3'6" enlargement) you can read distant billboards you couldn't even

see with the loupe. <p>

 

I really doubt the finest Schneider or Zeiss (or Mamiya) normal lenses

will beat that. <p>

 

The problem is, that's a 45x linear enlargement and even E100 grain is

hideous. The same shot on an MF camera needs much less enlargement,

so the grain is alot better. <p>

 

Which is why I'm here 8-) <p>

 

Frank

[mark_hubbard]

Thanks, Frank. I'll write you off-forum with a more specific question. Best wishes, Mark

[ryszard_stasinski1]

I don't agree that smaller grain is the only advantage of MF. There

are also some optic laws that make it 'better' than the 35 mm format.

At the same time this text explains why an optically worse MF lens

may appear to be _more_ efficient than an optically better 35 mm one.

 

<p>

 

I'll try to explain it on the following example: You are

photographing a Greek/Roman temple (or a court building in your city)

on a bright sunny day. The building is surrounded by grooved coulmns

which grooves produce dense and contrasty pattern of parallel lines

on your negative/slide. You have at disposal two cameras: Pentax K1000

and Pentax 67, two lenses: 50 f1.7 for K1000, and 105 f2.4 for 67, and

a converter that allows you to use the 105 lens on K1000.

 

<p>

 

So, you do three shots using: K1000 with 50 lens from the distance of,

say, 30m (100 feet), K1000+converter+105 from the approximately

double distance - 60m (200 feet), finally 67 with 105 lens, the

distance is rougly 30 m, once more. As can you see, the chosen

distances guarantees identical composition of all three shots.

 

<p>

 

Results? You measure the 'K1000+50' transparency and discover that

when comparing to the measurements on the columns the contrast

between bright and dark parts of grooves on the transparency

is diminished by... really don't know what number to say... 7%,

O.K.? Don't ask me _how_ to measure this, just assume that this is

possible. Then you take the 'K1000+105' transparency. The 105 MF

lens is not so well corrected as the 50 mm 35 format one, so, the

lines on the transparency are 'smeared' stronger than those on

the 'K1000+50' one. You measure that the contrast is diminished by...

once more a wild guess... more than for 50mm, of course, but not too

much... 10%? Finally, you take the MF transparency. The first

discovery is that the lines on it are two times wider, so their

'smear' by the 105 lens is much less disturbing than on the 35mm

format transparency. And now you can observe the intervention of

laws of optics - as the lines on the MF transparency are two

times less dense than on the 35mm one, the reduction in their

contrast is roughly two times smaller, too. So, you measure only

5% of contrast loss, 2% _less_ than for K1000+50mm!

 

<p>

 

Please, don't take too seriously all this percents. I want only

to illustrate the fact that the larger film allows you to get _more_

sharp and contrasty images even if your optics is _less_ efficient

than that for the smaller film format, and that this could have

nothing to do with film granularity.

 

<p>

 

Ryszard Stasinski

[eugene_crumpler]

The short answer: don't buy USED equipment, especially MF that probably has had heavy pro use. Now to be helpful. The sharpest 35mm lens I own is a 55mm micro-nikkor. At f11 it goes beyond my resolution chart. With tech pan and f11 and careful technique ,I can produce a B&W 16X20 that has the sharpenss of a 4x5 and the 4x5's in my camera club can't believe it. Tonality is another matter!

 

<p>

 

My best MF lens, a 55mm f4 on 67 pentax comes close to the micro-nikkor on the chart, but produces smoother tonality on a 16x20 print. I also do a whole lot less spotting !!! Although I am a graduate engineer and could plot graphs, charts, etc, I like to keep my hobby not to techical. My opinion is get your money back and buy a NEW pentax or mamyia for the same money!

[herb_gibson]

Twenty five years photography interest, including 10 years in photo

wholesale/resale has taught me that most pontificating about lens

sharpness is bs, by nerds who prefer talking to creating. Taking a

prejudiced stand on the merits of camera makes is the main point for

too many of us - cant say I'm never guilty myself! However, out of

interest, some snippets I've read which stand out:

 

<p>

 

I finally bought a Blad last year but I've been working overseas and

have not had time to use it. However, colour wedding shots I did ten

years ago did not have the sparkle of HB shots taken by friends. I

used Bronica, Mamiya, Rollei etc. I used massive tripods with big

Studio Ball heads. Rollei and blad same lenses? - yes, but rollei

focus screen holder is pathetic flimsy thing. I had terrible trouble.

Blad screen drops into solid machined opening. Beautiful. Your Blad

lens should produce mindblowing quality - have done for years. First

multicoated versions were T* in mid seventies. Better contrast than

older C types. Be careful, by and large Cs are chrome, T* are black.

However, HB produced a few Black Cs just before the changover. I know

- an unscrupulous dealer sold me one as a T* and I had to fight for a

refund! Cs have amber coating, T* has green/blue. Some people like the

lower contrast of the older lens however.

Norman Parkinson, famous British fashion photographer dropped his old

150, bought a new T* type and decided he couln't use it - contrast was

too high!

Remember, normal lenses are not designed for optimum sharpness close

up so macro lenses may produce dramatic performance on these subjects.

There are many reports of biting sharp Nikon micros.

The advice about not buying s/h is half right. Photo shops are full of

good amateur equipment bought on a whim and never used. However, Blads

are a pro favourite so a lot have been got rid of after starting to

give trouble. Buy only those that look mint.

Backs are notorious for giving trouble; you shouldn't have any play

there.

Remember, big tripods are best except where a frequency from the

camera co-incides with a natural frequency of the tripod and resonance

occurs.

The UK magazine Amateur Photographer for a long time judged all lenses

against the Carl Zeiss 50/1.7 for Contax - the sharpest ever tested.

It has now been surpassed by the Canon EF 135/2 L. However, figures

for Nikon seem to usually outdo Canon, especially at wide apertures.

(I use Canon!)Nikon has long had a reputation for high apparent

sharpness due to high contrast.

Leica fanatics countered the Carl Zeiss 50/1.7 claiming bench figures

were good because it was designed for flat plane film. However, real

film is slightly curved and Leica lenses (they argue) is designed for

this! Contax vacuum back argument anyone????

Finally, all reports I have read on Pentax 6x7 lenses say the are

fantastic. I've read someone uses pentax 645 with all 67 lenses

because of the superior quality. (Using only lens centre will help!)

Summary? Buy a good condition Hasselblad, get it checked at a HB

clinic use a sturdy tripod, mirror up, and focus carefully on an Acute

Matte screen. The camera handles beautifully, will endure loads of

hard work which flimsy Rolleis, Bronicas, etc dont, and its lenses are

good enough to have the best pros in the world raving. They must be

reasonable!

Finally, I read a couple of years ago that Hasselblad claim that they

cannot allow their lenses to be any sharper because of a possible

diffraction effect with film grain structure. I didn't quite

understand but it sounded interesting!

Straightest UK dealer:- MXV in Uckfield, Sussex. See ad in back of

Amateur Photographer. Categories are honest, return if not delighted,

one year guarantee, very nice people; what more can you ask?

 

<p>

 

Herb.

[s_p]

I think there is probably nothing wrong with your Hasselblad.

The problem is probably with your test ---- the 28 on 35mm and

the 80mm on 6x6 are giving you such different fields of

reference.<p>

Do a new test. Put a 50mm on your 35mm and an 80mm on your 6x6.

Take a picture where an object of a certain size, say, a window

in your wall that is 30 feet distant, occupies half the frame.

In a darkroom, make 11x14s where the window frame is the same

size in each print. The print from the Hasselblad will blow the

35mm away. If you do the test with slide film, project the

slides so they are the same size on the screen. Again, the

Hasse will produce the more detailed image hands down.<p>

The big jump in image quality with MF comes with the fact that

in order to get an enlargement, a great deal less enlarging is

necessary.