what does F1.8 or 1.4 give me?

Chrissiebeez_NL

hi fellow Dgrinners!

I regularly shoot at my sisters presentation event called 'pecha kucha' in Rotterdam and Amsterdam where presenters can show there work. i've mostly shot with my KM Z6 and it gave me fairly decent shots. now i upgraded to a 400D but with the kit lens i get the same results (if not less) then i used to. I use a tripod but also like to move around without it to get shots of people and different perspectives on speakers and i cant drag a tripod through the crowd (and my spot would be taken when i get back ) I can get fairly sharp shots with a shutterspeed of 1/10th - 1/15th of a second but with my kit lens i couldnt get the shutter under 1/4 to 1/8th of a second and then its just chance if someone moves or not. I'll show some photo's to get a feel of the lighting , these are all pretty ok but 90% i throw away because they are blurred



this was shot with 400D at 1/4th of a second at 18mm F3.5 with ISO 1600 and no exposure bias and looks good enough, but 90% of the shot at 1/4 i can throw away.



This was shot with my Z6 at 1/6th second F3.2 - ISO 160 and -2 EV. 1/6 worked here but it's an exception. the anti shake of the Z6 accompanied by a miracle moment of coincidental stillness on behalf of the speaker probably made this shot work.



this was shot with my 400D and kit. 1/10th of a second, F3.5 @ 18mm with ISO at 1600 and o EV.

how much do you think i can get in terms of shutterspeed with an 1.8 or 1.4 50mm prime or would an 2.8 zoom cut it here?
Its a big investment for me because these are the only nightshots i take so my need to invest in an expensive lens is low.

ziggy53

The difference between f3.5 and f1.4 is about 2 2/3 stops, so taking the last shot for instance, you could have used f1.4 at around 1/50 sec instead of f3.5 at 1/10th sec. DOF would be affected and your field of view would have been much less, assuming you mean a 50mm, f1.4, compared to 18mm.

A 50mm, f1.4 is a nice addition to your bag no matter how you want to justify it. It would not solve all your needs, but that's why you got the dSLR, so you could have flexibility in your solutions and abilities.

A lens with an f2.8 is not going to be a substantial improvement in exposure versus f3.5, but it will probably be a better lens overall.

Chrissiebeez_NL

hey Ziggy!

thanks for the fast reply! aside from the DOF and VOF 1/50 would be plenty to get sharp shots! i dont quite understand how you calculated the stop difference and then translated that to shutterspeed but what would the difference in shutterspeed be between a 1.4 and a 1.8? does the image quality differ a lot between the two?

seeker

ziggy53 wrote:

A lens with an f2.8 is not going to be a substantial improvement in exposure versus f3.5, but it will probably be a better lens overall.

Hey Ziggy -

Aren't f/2.8 lenses typically a constant aperture through the entire zoom range (if we are talking about a zoom lens here). Is that why you think they are a better lens overall?

Regardless, it makes them more $$

- Brian

ziggy53

Chrissiebeez_NL wrote:

hey Ziggy!

thanks for the fast reply! aside from the DOF and VOF 1/50 would be plenty to get sharp shots! i dont quite understand how you calculated the stop difference and then translated that to shutterspeed but what would the difference in shutterspeed be between a 1.4 and a 1.8? does the image quality differ a lot between the two?

f1.8 is about 2/3 stop less light than f1.4. There are more differences between the EF 50mm, f1.4 and the EF 50mm, f1.8 than just the size of the aperture.

The f1.4 version has better bokeh because there are more blades in the aperture and they are also a better shape. The f1.4 version is also faster to focus than the f1.8, but not by too much. The f1.4 is a much sturdier construction and is slightly better resolution wide open.

If you can afford the Canon 50mm, f1.4 I highly recommend it.

Nice review here:

http://photo.net/equipment/canon/ef50/

ziggy53

seeker wrote:

Hey Ziggy -

Aren't f/2.8 lenses typically a constant aperture through the entire zoom range (if we are talking about a zoom lens here). Is that why you think they are a better lens overall?

Regardless, it makes them more $$

- Brian

Brian,

Constant aperture "zooms" are usually of better quality overall, and they usually reflect this in their price as well.

I did presume that the original poster was talking about an f2.8 zoom and yes, that's what I was referring to.

Chrissiebeez_NL

wow thanks for the help! I'm going to think about the 1.4. but thanks for solving this puzzle for me!

judah

Hi Chrissiebeez_NL,
as Ziggy said you could get a much faster shutter speed with a 50/1.8 (even better with a 1.4), and as far as I know (I'm Nikon) the 50/1.8 is the cheapest lens you can buy. Unfortunately the shots you showed here where both at 18mm so with a 50mm you'd have a completelt different point of view. Just my 2 €/cents.

J.

Chrissiebeez_NL

hi judah!

yes, that would be the biggest handicap of the 50mm; you cant zoom in or out.. the second photo is made around 50 mm, maybe a bit more (Z6 exif is strange..) so that kind of shots would improve. and hopefully a lot of the people shots as well..

Chrissiebeez_NL

well thanks for all the help , i think im going to buy the 1.8 because it seems adequate for now and if it ever becomes more important i can always sell it with relativly no loss.

i'm curious how it will work with the faster shutterspeeds and the somewhat more creative demands that a fixed VOF brings. ill post some pics with the results.

claudermilk

You will learn to work with it. The first thing I did was replace my kit lens with a 50/1.8 for those kinds of low light situations. Shutter speed improved a whole lot. If you look at my site in the dance sections, you will see what f1.2, 1.4, 1.8, and 2.8 can do for you--and with moving targets.

I own and frequently use the 50/1.8 and 24-780/2.8 for this; I also am able to get my hands on an 85/1.2, 50/1.4, 70-200/2.8IS, and 300/2.8IS when needed. They all do well in this use, though none can touch the 50/1.8 for price/performance.

I think getting the 50/1.8 is a great move--everyone should have one.

sirsloop

You may also find that the 50/1.4 is a bit on the long side for a lot of work like what you are showing (on a 1.6x sensor). Its a fantastic lens otherwise!! Keep in mind, its a lot easier to control camera shake at 18mm than it is at say 30mm or 50mm. The longer you go the less the movement has to be to introduce shake.

The other big aperture lens you may want to consider is the Sigma 30/1.4 or the Canon 35/2. Both are fantastic lenses. The Sigma lens is along the same price line as the 50/1.4 and i'd take that lens in a hearbeat on a 400D. I actually use the 35/2 which is a super cheap and super potent little buzzer. Its build quality is sufficient... virtually identical to the old (and better built) 50/1.8 mark 1.

gpphotos

i was actually about to recommend the sigma 30/1.4...but they are tough to find. im currently looking for one myself for nikon. i have the sigma 18-50 2.8, which is a nice lens...i shoot a lot of theatre and stuff on stage with it...but that 1.4 will come in really handy methinks

the 30 1.4 and the 18-50 2.8 came out about the same time (part of the same series i think) so if the 2.8 is any indication, the 30 1.4 should do the job pretty well.

wish i could drop 2 grand on the nikon 28mm f1.4...why oh why did they have to stop making that lens

Chrissiebeez_NL

hi!

thanks for all the replies!

im currently going for the canon 1.8 mainly because of its price and im curious what this little gem will give me. if it works for me and i can get beter shots im sure ill go looking for something wider like the 30 or 35mm those are great suggestions. thanks!

LiquidAir

Here is a table I put together for calculating shutter speed & aperture combinations. Exposure Value (EV) is a number which represents the total light getting through the body to the sensor (taking into account both aperture and shutter speed). As an example 1/4s at f/4 is EV 6. If you set the aperture to f/1.4, EV 6 has a shutter speed of 1/30s. There are three variants of the table (click the buttons at the top) which should make it easy for you to figure all these relationships out.

http://www.liquidairphoto.com/ss_table.html

sirsloop

sigma 30 tough to find? Nawww! Maybe used cause nobody wants to sell theirs


http://www.bhphotovideo.com/c/product/381615-REG/Sigma_300101_30mm_f_1_4_EX_DC.html

mmmatt

Chrissiebeez_NL wrote:

hey Ziggy!

***snip*** i dont quite understand how you calculated the stop difference and then translated that to shutterspeed ***snip***

In whole stops: (you do the math for 1/3rd and 1/2 stops!) Bold indicates breaks in the mathmatical patterns.


Apertures (f-stops)
1
1.4
2
2.8
4
5.6 8
11
16
22
32
45
64

Shutter speeds

1sec
1/2
1/4
1/8
1/15
1/30
1/60
1/125
1/250
1/500
1/1000
1/2000
1/4000

Each step up/down is a "stop", and is simply a measurement of light. Each time you go up (decrease time) a shutter speed you must go down (make larger) an f-stop to compensate, or each time you go up (make smaller) an f-stop you go down (increase time) a shutter speed. This will asssure you achieve proper exposure. Your camera does this calculation for you in aperture priority and shutter priority modes. This is called the "law of reciprocity" (Read: reciprical, or that things change symetricaly). Knowing this simple rule can help you understand a LOT about exposure, lens speeds, and basic photography.

Best way to think about it is a bucket of light. If you cut the time the faucet of light is on (shutter speed) by a stop, then you have to add a larger flow of light (f-stop) with the aperture of the lens to compensate, and vice-versa. Less than 1/1000 shutter speed and more than 1 sec (or at 1 sec for some schools of thought) will require compensation for reciprocity failure, but that is another lesson in itself, and to be honest I don't know how/if that rule translates to digital...
The layman looking at lenses will think that the difference between f1.4 and f2 is minor compared to the difference between f2.8 and f4, but it is the same... just 1 stop! You pay BIG dollars for 1 stop when it comes to lenses!!!!

ISO's are a similar situation and are the last link in understanding proper exposure...


ISO's in full stops:

25
50
100
200
400
800
1600
3200

Soooo... a f1.4 aperture, shot at 100 ISO is the same (in terms of exposure) as an f8 shot at ISO 1600. Just one more bit of proof that Canon is so much better than Nikon , or more importantly, why digital camera's open up the creative range of photography by not being married to ISO adjustments (or color temperture!!!) only every 36 shots.




Matt

claudermilk

Good post. Bryan Peterson's book Understanding Exposure (http://www.amazon.com/Understanding-Exposure-Photographs-Digital-Updated/dp/0817463003/ref=pd_lpo_k2_dp_k2a_3_img/104-5816645-7435919) is frequently suggested for these basic kinds of questions. And for instan feedback on how shutter speed and aperture relate to exposure and DOF: http://www.photonhead.com/simcam/shutteraperture.php

ziggy53

LiquidAir wrote:

Here is a table I put together for calculating shutter speed & aperture combinations. Exposure Value (EV) is a number which represents the total light getting through the body to the sensor (taking into account both aperture and shutter speed). As an example 1/4s at f/4 is EV 6. If you set the aperture to f/1.4, EV 6 has a shutter speed of 1/30s. There are three variants of the table (click the buttons at the top) which should make it easy for you to figure all these relationships out.

http://www.liquidairphoto.com/ss_table.html

Please note that Pathfinder has added this thread comment, along with the link to the table, to "The Best of Technique"

http://www.dgrin.com/showthread.php?t=56682

Thanks LiquidAir for the Table and explanation.

Chrissiebeez_NL

claudermilk wrote:

Good post. Bryan Peterson's book Understanding Exposure (http://www.amazon.com/Understanding-Exposure-Photographs-Digital-Updated/dp/0817463003/ref=pd_lpo_k2_dp_k2a_3_img/104-5816645-7435919) is frequently suggested for these basic kinds of questions. And for instan feedback on how shutter speed and aperture relate to exposure and DOF: http://www.photonhead.com/simcam/shutteraperture.php

already ordered! should be in my mailbox anytime soon.

Chrissiebeez_NL

woohoo!
waaah! i love it!

i've bought the 50 1.8 second hand with a hoya filter and a lenshood and i love the DOF at 1.8. the focus is excellent, shutterspeeds are totally workable even at very low lights ..
i cant wait to do some shooting at night
thanks for all the help!

ziggy53

Chrissiebeez_NL wrote:

waaah! i love it!

i've bought the 50 1.8 second hand with a hoya filter and a lenshood and i love the DOF at 1.8. the focus is excellent, shutterspeeds are totally workable even at very low lights ..
i cant wait to do some shooting at night
thanks for all the help!

Very cool! Good shooting.

Chrissiebeez_NL

i did my first shooting gig yesterday with my 50mm 1.8 and loved the 'action stopping' capabilties of it! no more blurry people!! its hard to shoot with a fixed 50mm lens because half of the time your too close to your subject and have to walk backwards through the crowd to even fit your subject in the frame i'll get used to it..

here are a few shots from wednesday:












thank you all for the suggestions and help! i'm really loving this lens!